By AP Guide Master File 2514

The Complete Backyard Aquaponics Guide 2014 Green Acre Aquaponics, Inc. Page 1

The Complete Backyard Aquaponics Guide

Table of Contents

Section 1: What is Aquaponics? .... 3

The Nitrogen Cycle ..... 5

Water Quality and Sources ..... 7

The Role of pH ... 9

The Numbers - Important Levels... 13

Dissolved Oxygen................ 15

Water Quality and Testing .............. 16

All About Cycling .. 17

Salting Fish ....................................................................................................................................... 18

Fishless Cycling .. 20

Cycling with Fish. 21

Section 2: Plants, Fish, Media and Worms

Insect Control .. 23

Plant Care 24

Seeding/Planting . 27

Fish and Plants .. 27

Seeding/Seedlings .. 28

Fish Handling .. 29

Media and Worms .. 30

Section 3: Components and Construction

Auto Siphons . 33

Plumbing it All Together . 34

The System Build . 35

Construction Basics 37

Construction Terminology/Notes . 38

The HomeHybrid System Detail . 40

Materials List . 42

Tool List .. 43

Build Instructions 44

Raft Fabrication .. 59

Copyright Statement

This material copyright 2013 by Green Acre Aquaponics. Copying or using portions of or excerpts from

this material without express written permission from the authors is prohibited by law. Please only use

this guide to fabricate the system designs herein for your personal use. Thank you!


Section 1

What is Aquaponics?

According to the Aquaponics Association, aquaponics is a synergistic growing technique in

which both fish and plants are grown together in the same system. The fish waste feeds the

growing plants using organic hydroponic techniques and the plants, in turn, clean and filter the

water that is returned to the fish environment. Thats it in the nut shell, however if we examine

this simple definition a bit deeper and consider the term synergistic, we see how incredibly

accurate it is. According to Dictionary.com, synergism is defined as

The interaction of elements that when combined produce a total effect that is greater

than the sum of the individual elements, contributions, etc.

If these elements, the fish and plants, were isolated, they would simply just be the growing

technologies known as aquaculture and hydroponics, however when we combine the two,

magic happens. Well, its really not magical, but this combination is such a perfect replica of

nature, it makes aquaponics one of the most efficient growing methods ever developed. By

mimicking nature, we can maintain the same parameters in a manmade container.

In doing so, aquaponics solves some of the most challenging aspects that face both the

aquaculture and hydroponic industries. On the fish cultivation side of things, when the

aquaculture industry transitioned to a technique that was coined Recirculating Aquaculture

Systems or RAS they drastically improved their yield per gallon, but created a fish waste

management issue. Fish could be cultivated at a ratio as high as 3/4 of a pound per gallon, but

this density meant a tremendous amount of fish waste and a problem for its disposal.

Considering that aquaculture was experiencing tremendous growth internationally, the industry

began to look for solutions to its ever growing problem.

Much of the research that aquaponics is based upon today was the result of one mans

quest to solve this aquaculture industry issue. Dr. James Rakocy who spearheaded the

department at the University of the Virgin Islands started out with a background in aquaculture.

His research there soon led him to explore aquaponics as a way to utilize the problematic fish

solids in a recirculating aquaculture system that incorporated plants as a tremendous filter for

the minerals that were essentially a byproduct that could be generated by the waste. Now

these fish solids, despite still needing to be removed from the system, could be used to grow

food which in turn filtered the water for the fish. This solution could help to minimize the


incredible daily waste of water by aquaculture facilities that was needed to preserve the water

quality for the fish and at the same time was terribly polluting natural water ways.

Hydroponic growing or the soilless cultivation of plants, also struggled with several of its

own issues that aquaponics can solve. Hydroponic growing requires the input of expensive

manmade chemicals that must be constantly replaced, monitored and purged. All three of

those things can make hydroponics not only costly, but difficult to maintain and the disposal of

the salts and chemicals left over after the nutrients are absorbed problematic. Aquaponics

never has the need for store bought chemicals for plant growth and an aquaponic system rarely

needs to be purged. Monitoring and testing can and should be frequent in a commercial

setting, but certainly not as critical as in a hydroponic system.

So when aquaponics combined these two technologies, practically all of the issues were

solved and it can also boast being one of the safest and most sustainable ways to grow food.

When comparing it to traditional agricultural growing methods, it solves most of the problems

there too. Nutrient depletion is not an issue, large petro chemical machinery is not required,

chemical fertilizers are not needed and pesticides cannot be used. The things that make

agriculture the most environmentally taxing industry of this century as well as producing

nutrient depleted, chemical laden foods is not even the slightest possibility in the aquaponic

world. Perhaps aquaponics cannot grow every crop that is grown traditionally, but it could

certainly eliminate much of the burden that modern agriculture enacts on our environment and

minimize the nearly 90% of our freshwater resources that is consumed by growing food for

both humans and the animals we eat.

Another incredible advantage of growing aquaponically is that it can be done literally

anywhere. Nutrient rich soil is not a necessity; in fact soil is not necessary at all. Aquaponics

can be done on an old Kmart parking lot or in an empty warehouse right in the middle of urban

sprawl and industrial complexes. Large plots of land are not required and different aquaponic

growing techniques can be combined to best utilize space and optimize growth. Minimal water

is needed so it is even a very viable option for desert areas such as the middle east or drought

stricken areas like Australia. How about Japan? The Tsunami of 09 made more than 40% of

viable farm land inert. When nature ravages the earth, aquaponics can still produce food.

It certainly seems like aquaponics is the answer. It solves so many of the issues that face

our sister agricultural industries and one must wonder why it hasnt been totally embraced and

become the predominant way to grow food. Give it time. It just has to grow and prove. It is

and will be scrutinized and the industries that are threatened will seek to find flaws, but like any

new thing, it takes time to get entrenched and rooted, but then it will prosper and grow just

like the plants in an aquaponic system. All we must do is provide the symbiotic elements and


when combined, they will produce a total effect that is greater than the sum of the individual

elements or contributions. We call this aquaponics.

The Nitrogen Cycle

The nitrogen cycle is the key process that makes aquaponics work. Often times, people refer to

the fish as the fuel in an aquaponics system, but actually we should consider the fish as the

engine and the bacteria as the fuel. Of course the actual fish food fuels the fish, but without

the presence of this beneficial bacteria, the whole process wouldnt work. An aquaponics

system requires what is called a biofilter, which can take several forms ie. a media bed, a grow

troughs surfaces and even the plant roots. It is in this biofilter where the nitrogen conversion

actually occurs, as these biofilter surfaces give the bacteria surface to colonize. The conversion

then takes place when the bacteria convert the first element of fish waste, ammonia into the

most usable form of nitrogen that plants can utilize to grow.

All waste processes from fish produce ammonia, a nitrogen and hydrogen

compound(NH3). Both the solid and liquid waste, the actual fish poo and pee, as well as what

is emitted via respiration through their gills generate ammonia. This ammonia in its nitrogen

and hydrogen compound stage is highly toxic to fish. The only means of removing this

ammonia is by dilution and by replacing sometimes as much as 70% of the system water or by

bringing in reinforcements, the nitrifying bacteria. Without these armies of bacteria, the fish in

an aquaponics system would be sitting ducks, or well, sitting fish! Fortunately, we can

introduce this nitrifying bacteria and effectively create the nitrogen cycle that converts this

otherwise useless and toxic ammonia to a usable end product, a nitrate(NO3).

The first essential nitrifying bacteria in the nitrogen cycle conversion is an autotrophic

bacteria called a Nitrosomonas. This aerobic autotroph, or an oxygen dependent organism,

feeds on ammonia and in consuming the ammonia excretes what is known as a nitrite(NO2).

However the conversion process cannot stop there as unfortunately, these nitrites are even

more toxic to fish then the ammonia! Fortunately however, another aerobic autotrophic

bacteria then converts the nitrites to the nitrates. (Bernstein, 2011)

Our second heroic nitrifying bacteria is another aerobic autotroph called Nitrospira sp.

The identification of Nitrospira is actually a relatively new discovery, as up until recently,

scientists thought that this second nitrifying bacteria was actually a Nitrobacter. As the

Nitrosomonas do their work and convert the ammonia to the nitrites, the Nitrospira then

convert the nitrites to nitrates. Now this final conversion creates a nitrogen compound that is

actually the most readily usable form of nitrogen that plants can take up, the nitrate.

(Bernstein, 2011)


Figure 1.1 - Heres what the conversion process looks like:

These bacteria and their ability to replicate and proliferate can be affected by different

variables in an aquaponic system. We mentioned earlier that both nitrosomonas and nitrospira

are aerobic autotrophs or organisms that require oxygen to survive and thrive and also feed on

inorganic matter, the ammonia and nitrogen. Well oxygenated troughs and media beds are

not only necessary for good plant health and growth, but for bacteria health and sustenance as

well. In the absence of oxygen, not only will these bacteria die off, but their departure will

allow heterotrophic bacteria that typically feeds on the organic matter in an aquaponics system

to actually convert nitrates back into ammonia and nitrites. This process is called dissimilation

and can cause dead or anaerobic zones in grow beds. When this anaerobic activity takes place,

not only is more ammonia created, but in the already low presence of oxygen, this process will

actually steal more of it. Typically these anaerobic areas will have a foul smell as the ammonia

is released. (Bernstein, 2011)

Another critical component in managing good bacterial health and numbers is

temperature. Nitrifying bacteria are happiest at 77 - 86F. At 64F, growth is inhibited by as

much as 50% and below 50, reduced as much as 75%. At freezing temps or 32F, these

bacteria will not survive at all. (Industries, n.d.) Due to the bacterias susceptibility to

temperatures, minimizing temperature swings is critical not only for fish health but bacterial

health as well. Low temps will typically affect fish food intake and as a result the system will

see a decrease in ammonia. However along with this decrease in feeding and the resulting

ammonia waste product, the cold temps will also inhibit bacterial growth, so theoretically an

aquaponic system will remain in balance under these conditions as both are lessoned. Upon

the water warming, the aquaponic operator must be careful to not overfeed the fish until the

bacteria can repopulate in the warmer temps and then keep up with the amount of ammonia

being generated.

Ammonia

(NH3)

Nitrites

(NO2)

Nitrates

(NO3)

Nitrosomonas

Nitrosomonas Nitrospira

Nitrospira


pH is another factor that can inhibit bacterial growth and much like temperatures, there

is an optimal range. Although they require a pH range of 6.0 to 8.5 in order to metabolize and

reproduce, Nitrosomonas actually prefer 7.8 - 8.0 and 7.3 - 7.6 for Nitrospira. 6.0 is a very

critical range and below 6, all conversion is compromised. (Hill, 2008)

A couple other factors that can affect nitrifying bacteria are sunlight and chemicals. The

Nitrosomonas or the bacteria that convert the ammonia to the nitrites will actually replicate

faster than the nitrospiras and at start up can cause what is called a nitrite spike or where the

ammonia is being converted to nitrites faster than the nitrospira can convert the nitrites to

nitrates. Being that nitrites can be harmful to fish, sunlight can be used to temporarily thwart

nitrosomona growth until the nitrospira bacteria can keep up. We dont advocate the addition

of any chemicals, whether it is a pesticide or growth agent to an aquaponics system. Chemicals

may not only kill the bacteria, but the fish too.

Water Quality and Sources

Water quality is a critical component in an aquaponics system. Not only does it insure a good

environment for your fish, but every other living organism in your system, the plants, the

bacteria and the worms. Starting out, your water source will play a key role in your system

health and when also having to top up or top off the system. Both through evaporation and

through the process of respiration and transpiration of the plants, water is lost in a system.

Therefore insuring the quality of the water you add to an existing thriving system is paramount.

There are a few commonplace sources of water and a couple not so typical water sources. First

let's look at the common ones.

If you live in an area where you have city water, odds are you will have a chlorinated

water source and a good likelihood of having chloramines in your water as well. Chlorine is a

highly effective disinfectant and is added to municipal water supplies to treat the water and

minimize the growth and/or kill bacteria. Red flags should be popping up! Not only will

chlorine kill the bacteria in an aquaponic system, but it can also kill the fish. Fortunately

chlorine is easy to remove from water as it will burn off or off gas out of water. Simply fill the

system up, turn on the pump and air blowers and run the system for a day or two. The chlorine

will effectively burn off. This takes a period of at least 24 hours but will also give you a good

day or two to just observe your system flow for the first time and insure that everything is

flowing as it should before adding fish or bacteria. Be sure to have a chlorine test kit or

purchase some test strips to be sure that the chlorine is gone. Once you have insured there is

no longer any chlorine present, it is safe to begin the cycling process for a new system.


From time to time however, you will have to top off your system. Depending upon the

time of year, the temperature and humidity levels, your system will lose water at different

rates. In Florida in the summer, we have to add at least 500 gallons every 10 days to our

commercial system. Of course for a small home system, that amount will be much less, but if

you are on city water, what will that mean for you? It means that you should have a reserve

tank filled with water at all times that has sat for at least 24 hours to burn off the chlorine and

then covered to prohibit algae growth. For ease of transfer you can have a small submersible

pump and when the system requires water, simply pump your chlorine free water in to a

trough or transfer it manually with a bucket. Fill up your reserve tank and repeat the process.

The next very common additive in city water supplies is chloramines. Chloramine is a

much bigger problem than chlorine as it is a derivative of ammonia by substitution of one, two

or three hydrogen atoms with chlorine atoms, but unlike chlorine, will not simply burn out of

water. Again it is used as a disinfectant and will kill both fish and bacteria. The only effective

way to remove chloramines from water is by treating it with products such as Chloram-x, which

can be purchase at Aquatic Ecosystems and aquarium pet stores. There is another product

called Amquel Plus which is exactly the same as Chloram-x, but it has not been certified for food

fish. Check with your local municipality to see what chemicals you might be dealing with as it

can save you some considerable time, cost and headaches.

Well water is another very typical source of system water. While there is no concerns of

chlorine or chloramines in well water, according to Dr. Wilson Lennard, some well water can be

Daves Experience with Chloramines

Dave was what we liked to call our apprentice. He was the first and only attendee at our very

first farm tour and after talking about aquaponics and the system for a couple hours during a

raging storm, Dave asked if we would like some help in exchange for teaching him how to build

and operate a system. Well, sure! After several months and Dave trekking across the state once

a week, Dave started his own system. Rather than doing what is known as a fishless cycle, Dave

netted several Tilapia from a friends pond and filled up his fish tank. He was ready to go!

For some reason the ammonia kept spiking despite Dave doing everything he should be doing.

Finally, after some research, thousands of gallons of water changes and lots of wasted bacteria,

Dave discovered his city water had chloramines. Check with your city first. It can save you a

whole lot of grief.


rich in carbon dioxide. (Bernstein, 2011) Much like chlorine though, filling up the system and

turning on the pumps and blowers can aerate the water and burn off the carbon dioxide. The

presence of carbon dioxide can kill fish and it is better to just fill up and run the system for a

day or two and eliminate any risk. Again, take this time to observe water flow and insure

nothing is leaking or not working correctly. Other than the possible presence of carbon dioxide,

or extremely high sulfur, there is little chance of anything being seriously detrimental in well

water.

A few other options for water supplies are rain catchment, agricultural water and

natural water sources. These can pose their own set of issues and again exercise caution. Rain

water is generally safe but can be acidic. Test the pH and or have the water tested to find out if

there may be anything harmful present. Ag water that is often in large culverts in agricultural

areas can often times be contaminated by runoff from chemical fertilizers, pesticides and other

toxins. Have this water tested! Last, natural water supplies are likely safe. Odds are they are

already teaming with life, but the risk here is introducing some kind of fish disease or organism

to your system that you cannot identify, regulate or eradicate. Ideally, just check your water

source and insure you are not starting your system with something that will create a problem.

The Role of pH

Aquaponics systems are very intimately related to pH and maintaining a balanced and

appropriate pH is essential for system health. First though, you must have a good

understanding of what pH is. If we think back to our early days in Chemistry class, we can

probably remember a pH chart alongside a Periodic table somewhere on the wall in our science

classroom. That pH chart would have showed a range of 0 to 14 with 7 being in the middle and

neutral. Anything from 0 to 7 was acidic and anything from 7 to 14 was basic. Pretty simple,

right? Also each whole number is a multiple of 10 so as it progresses away from neutral and

becomes more basic, a pH of 8 is 10 times more basic then a pH of 7 and a pH of 9 is 1000 times

more basic then a neutral pH. It works exactly the same way for the acidic side of the scale and

although one whole number does not seem too drastic, when the multiple of 10 is taken into

consideration, a pH of 5 is very acidic and will spell trouble for an aquaponics system.

The aquaponic system in general and each of the living components in the system have

optimal ranges. The fish, the plants, the bacteria and even the worms in a hybridized

media/DWC system have ideal ranges and basically a compromise must be reached so that

each can reside in the most conducive range.


Figure 1.2 - Optimal Ranges for Aquaponics System Living Components

Fish 6.5 8.0

Plants 5.0 7.0

Bacteria 6.0 8.0

Worms 6.0 8.0

(Bernstein, 2011)

Considering the above ranges it would appear that the optimal range for the system and overall

health of the fish, plants, bacteria and worms would then be somewhere between 6.5 and 7.0.

This is a safe range for the fish and will also allow the plants to take up nutrients as both highly

acidic or highly basic conditions can create an issue called nutrient lockout.

pH is usually dictated by the pH of the systems water source. If your available water

that both initially fills your system and tops it off tests at 7.5, then this will be your pH starting

value. Although, other factors will influence pH as well. The media comprises a significant

portion of the system and you must insure that the media is inert, meaning it will not influence

system pH. Often gravel can have a limestone base or residue and this will automatically make

the pH gravitate up into the basic ranges. If you use either Hydroton or Expanded Shale, either

media is inert and will not affect pH. However if you want to use another type of media and

you are unsure how it might affect pH, check first with the supplier. Some suppliers can furnish

reports that detail the actual pH of the substance and its effects on water when submerged. If

this type of data is unavailable, a simple test can be preformed submerging some of the media

in some distilled water for a period of at least 3 days. Be sure to first test the pH of the distilled

water to verify that it has a neutral pH and then after 3 days, test the pH of the water with the

media submerged. Any variation in the pH as a result of the media will be indicated.

The nature of the biological processes that take place in an aquaponic system, namely

the nitrification cycle or the conversion of ammonia to nitrites and then nitrates will cause a

downward trend in pH. An aquaponic system will therefore over time always gravitate down in

pH. Due to this natural downward gravitation, often systems require adjusting the pH up or

what is referred to as buffering. There are many additives, buffers or pH adjusters that can be

used to raise pH and normally a form of calcium or potassium is used. The most common forms

of buffers are hydroxides or carbonates. The difference between the two is that the hydroxide

is a chemical component and if not metered in carefully can actually swing the pH beyond the

optimal range you were trying to achieve. In large commercial systems that use hydroxides,

typically there is a system component called a base additions tank where the hydroxide is

slowly and carefully added. The solitary use of calcium only will adjust the system pH up but


the system and plants will not benefit from the addition of the potassium, so it is recommended

that both are used and alternated.

A very nice feature of using carbonates to buffer pH is that they will not create pH

swings. When the system reaches a neutral pH, the carbonate will become inert in the system.

If an abundance of carbonate is then in the system, as the pH begins to gravitate downward

again, the carbonate will re-activate and begin to buffer the pH back towards neutral. Some

common carbonate buffers that are used are things such as egg or sea shells which are can be

placed in a mesh bag and placed into a system. This method however can be hard to meter. A

powdered form of Calcium carbonate that is essentially crushed coral can be purchased at

hydroponic stores and added into the system in small amounts. A shift in pH will not be

instantly noticeable, but gradual additions will insure too much carbonate is not added at one

time and also allows the carbonate to dissipate into the system better.

Some factors can cause pH to gravitate upward too, but this is more of a rare

occurrence and can be an indicator that something is wrong. Usually a non-inert media is the

culprit such as limestone laden gravel. The basic nature of the limestone will cause the pH to

rise. Even a non-inert system component can cause the issue. Be sure to seal any concrete

tanks or troughs as the lime in concrete can spike pH and will alter system pH over a very long

period of time. Other agents that can cause pH to rise are anaerobic zones or areas where

some type of organic matter from plants, roots and even some media such as Coconut Coir is

decaying and breaking down. When this occurs, ammonia is released, oxygen is absorbed and

pH can rise. Over time media that falls out of the net pots in the deep water troughs will

eventually build up and will need to be cleaned out of the troughs before they present this

anaerobic condition. This also can happen in the media beds. These dead zones can occur from

excessive root growth and solids build up that blocks water flow, creating 'channeling' or

How To Adjust pH with Calcium and Potassium Carbonates

Add an 1/8 cup of Calcium or Potassium Carbonate to 2 gallons of system water in a bucket. Stir

carbonate into water until the carbonate begins to dissolve and is dispersed throughout the

bucket. Slowly add the carbonate-water solution to the radial flow clarifier. . Test for the next

two days and monitor the systems pH. The nature of the Carbonate will not allow the pH to go

beyond 7.0 or neutral, however adding too much carbonate can leave a significant residue in the

grow troughs. If after two days the pH has not buffered up, repeat the process with another 1/8

cup of the other carbonate. Continue to alternate the carbonates as needed.


limited paths for water flow and as a result will reduce oxygenation to the bed. The area will

typically smell bad and the plants there will not look healthy. Another way to test for anaerobic

conditions in media beds is to test the pH of the water flowing out of the beds. If the pH is

higher than the system values, it could indicate dissimilation is occurring. The area will typically

smell bad and the plants there will not look healthy. Plants in these areas should be removed,

the blockages cleaned out and water flow returned.

There are a few different additives that can lower pH. Any time pH is significantly higher

than 7 or neutral, some type of acid must be added to lower pH or lower a basic condition.

Slight readings above 7 are not problematic and with some patience and time, one can allow

the natural lowering of the pH with the nitrification process to lower the pH of the system.

Phosphoric or nitric acid can be added and also have some added benefits of lending

phosphorous and nitrates to the system that the plants can utilize. Other acids such as Muratic

or Hydrochloric acid can be stressful for the fish. Vinegar is a mild acid, but sometimes not

enough to lower pH. Avoid citric acid as it will annihilate the bacteria as it is an antibacterial

agent and will crash an aquaponic system. Last, hydroponic stores and aquarium stores sell

products to lower pH that are generally called pH Down. Insure that you use a product that

has no sodium or citric acid.

Acids are not OMRI approved and may not be a very desirable additive to your organic

system, after all Muriatic acid is what is added to swimming pools or is used to etch concrete.

Basically the strong acid eats the basic lime composition of the concrete. Be very careful when

handling acids. Be very careful when handling acids and wear eye protection.

API Freshwater Test Kit

In the event you need to lower your pH, likely you will need to perform a titration test

to determine how much acid you need to add in order to lower the pH to the desired range and

not lower it too much. Also keep in mind that a drastic shift can be stressful for your fish so the

We recommend the API Freshwater Test Kit for monitoring pH

and other important levels in your commercial system. This kit

tests not only pH, but High Range pH, Ammonia, Nitrite and

Nitrates. Compared to less accurate test strips, it is also far

more economical with over 800 tests for $24.95 from The

Aquaponic Source. Comparatively, one tube of Ammonia test

strips for 50 tests is $15. All tests can easily and accurately be

performed in 10 minutes.


last thing you want to do is pour in a gallon of acid and swing pH several points at once. Fill a

gallon jug with system water and test the pH. Record what the current measurement is. Now

add one drop of your adjusting acid. Cap the gallon jug and invert several times. Now fill up a

test vile and test the pH. Record the new measurement and note how much it altered the pH.

This now indicates for example, that one drop of Muriatic Acid will lower one gallon of system

water .2 on the pH scale.

Now extrapolate your data. One drop is equal to 1/20th of a milliliter. So if it took 1

drop to change the pH of one gallon .2 points and you have a 375 gallon system(HomeHybrid

with 100g tank), it will take 18.75ml to shift the system down .2 points. Heres the math:

The Numbers - Important Levels

Now that we have explained the important elements of the aquaponic system, here are some

important levels to keep in check when operating a system.

In relation to the nitrogen cycle, nitrites, nitrates and ammonia are the three elements

that will be regularly monitored. Once the cycle is established, normal operating levels should

remain constant in the system. Nitrates may climb, but both ammonia and nitrites should

remain very low. Typically, in a healthy system where the bacteria is successfully converting

the ammonia over to nitrites and nitrates, ammonia levels should remain as low as 0 and no

higher than 1ppm. If ammonia is above 1ppm, it is an indicator of a potential problem.

Ammonia will normally remain consistently low unless there is an anaerobic condition

somewhere in the system. If organic matter is decomposing in the system, the process can

spike ammonia. Another potential culprit can be dead or dying fish. Fish will emit a lot of

In this example, 1 drop will lower 1 gallon .2 points. Therefore to figure out how much for 375

gallons,

1 drop = 1/20th ml or .05 ml

Multiply 375 x .05 ml = 18.75 ml

For a reference, 500ml = 0.132086 gal or 0 gal and 1.05 pints

DO NOT ARBITRARILY ADD ACID TO YOUR SYSTEM! IT IS A VERY STRONG ADDITIVE AND CAN

CRASH A SYSTEM QUICKLY. UNLIKE SOME BUFFERS THAT REACT SLOWLY AND WILL STOP AT

NEUTRAL, ACID WILL ALTER IMMEDIATELY AND CAN CREATE A DRASTIC SHIFT.


ammonia as they are dying and a dead fish or two in the bottom of a fish tank can easily cause

the ammonia to creep up. The last and least likely scenario is a large loss of nitrifying bacteria

or nitrosomonas, so that they are incapable of keeping up with the amount of ammonia being

generated, however this can occur is pH is allowed to get very acidic or if critically low temps

are reached. Remembering that pH has a natural tendency to gravitate down, if allowed to go

unchecked, low pH levels can kill or inhibit nitrifying bacteria or nitrosomanna growth to the

point that the ammonia cannot be converted quick enough and ammonia can then spike. Most

test kits only go down to 6.0 for pH testing, so be sure to monitor often as once below 6.0,

there is no way to determine how dangerously low your pH might be.

In the event the ammonia is escalating, the first thing to do is try to determine the

source. In the meantime, stop feeding the fish. Fish can easily go two weeks or longer without

being fed. They may not be happy about it, but they will survive. By ceasing feeding, you can

minimize any more ammonia from being contributed to the system. An ammonia of 3ppm can

be stressful to fish. Anything above 3ppm, a partial water change must be done. It is the only

way to re-establish a lower ammonia level. Over 3ppm will necessitate exchanging at least half

the system water. A reading over 6ppm, as much as three-fourths of the system water will

need to be exchanged. However, outside of this occurrence at start up, there would have to be

something seriously wrong in the system to spike ammonia that high.

Nitrites are much like ammonia in that unless there is a serious problem, nitrites should

remain within their optimal ranges. This normal operating range is between 0 and 1ppm.

Nitrites over 6ppm are hazardous to fish. If nitrites are climbing at any other time then startup,

something has compromised the bacteria that converts nitrites to nitrates. Extremely cold

temps can contribute to this, however it is a rare occurrence. However the fact that the

nitrosomanas or the autrotrophic bacteria that converts the ammonia to a nitrite is UV

sensitive, nitrite spikes can be mitigated by exposing the system or water to sunlight. Removing

one/fourth of all the rafts for one day will typically lower nitrite levels.

pH

Figure 1.3 average pH

Fish 6.5 8.0

Plants 5.0 7.0

Bacteria 6.0 8.0

Worms 6.0 8.0


pH was covered quite extensively in the pH section. Optimal ranges for pH are 6.5 to

7.0. Low pH means acidic and can be buffered up with Calcium and Potassium Carbonates and

high pH is basic and can be lowered with various acids or vinegar.

Dissolved Oxygen (DO)

Dissolved oxygen(DO) is the life force in an aquaponics system. It is not only paramount for the

fish to live but also for the plants to grow in a DWC type system. For the plants in a media bed,

the oxygen is infused by the action of the quick draining of the water via a bell siphon and

oxygen being drawn down into the media. A raft or DWC trough does not have any mechanism

in place to provide oxygen, therefore it must be supplemented. Because oxygen is delivered

throughout the system though, even the media beds will benefit from the additional aeration.

How much aeration is enough and how much is too much? Minimum sustainable and

comfortable DO levels for many fish such as Tilapia, Catfish and Koi should be 5.0ppm. Be sure

to become familiar with the oxygen requirements for the fish you select to cultivate. For most,

if the system gravitates towards 4.0, the fish will survive but this figure is an absolute minimum.

Anything below 4.0 can mean fish mortalities, stress and the possibility of disease settling in

due to a stressful event. Hovering somewhere between 5.0 and 6.0 will be perfect for most

fish. Some can thrive in less DO conditions, others will require more.

Test strips and kits are available for testing DO and although they are not as accurate as

a meter, can indicate if there is adequate DO. Different conditions can alter DO or cause it to

fluctuate. As the fish grow, the presence of oxygen in the tank will change and you will possibly

have to increase the amount of DO. Other factors will influence DO such as water temperature,

barometric pressure and altitude. Decomposition of any type of organic substance will also

consume oxygen. Inhibit algae growth by covering all water as much as possible from sunlight.

Algae has a limited life spans and although they will contribute to oxygen levels during the day,

the metabolic processes that occur overnight and also with decomposition will actually steal

oxygen.

If the fish appear to be 'gulping' at the surface of the water, this can be an indicator of a

low oxygen conditions. Be sure to not confuse this with the gulping behavior that is normal

after feeding. If it occurs at any other time, check DO levels immediately.


Dissolved oxygen is such a critical component, that in the absence of it, the fish have a

very limited window of survival. Typically, in low to moderately stocked tanks, one hour is the

critical threshold to go without oxygen. In higher stocked systems, that timeframe is even less.

It is advisable to have a backup system in place which may be as simple an inverter that you can

plug into your car to keep your pump running and air in your system if the power is down for a

length of time.

Figure 1.4 - DO

< 3.0 ppm DO Critical! Get air immediately

3.0 4.0 ppm Potentially can cause mortalities, stress fish

4.0 5.0 ppm Ok

5.0 6.0 ppm Optimal for most fish

Water Quality and Testing

Water quality is something that is monitored daily. Every time you approach your system, you

will become accustomed to observing the water quality. You will be familiar with the color, the

odor, the clarity, the amount of solids suspended and the water level. You will gain a level of

intimacy with your system from your daily interaction and just a simple visual inspection can

impart if something is amiss. A water quality rule of thumb to always remember is to always

keep tanks and troughs shaded to both inhibit algae growth and to protect the nitrifying

bacteria.

Use a test kit to check water quality and levels. You will test for pH and nitrates more

often than ammonia, nitrites or DO. As mentioned in the cycling section, you will test all levels

and also test more frequently until your system matures. While cycling, you will test as often as

daily and then every other day after cycling has occurred. Eventually after about 4 months you

will test once to twice a week and then more often as needed if a problem arises. Systems can

get out of balance and although both the fish and plants can be good indicators of issues, a

problem that could compromise plant growth and harvests for a length of time could have been

averted by frequent testing. The frequency of how often you top of your system will also

influence how often you test. If you raise or lower pH with each addition, testing will be

necessary to restore desired levels.


All About Cycling!

If your idea of aquaponics cycling is something like the above picture, then we have a lot to

cover! Actually, the process of starting up an aquaponic system and establishing a biofilter is

called cycling and there are a few different ways that can occur. The way you elect to start

yours will likely be based upon the length of time you want your cycle to take, as each one

varies. If you have plenty of time to kill, you can do absolutely nothing. Just because an

aquaponics system is a living ecosystem teeming with life, the natural processes that occur in

any fresh body of water will occur in an aquaponics system, however it will occur over a long

period of time, easily 8 weeks or longer. If you are starting up a commercial farm, the last thing

you would want to do is wait for a non-catalyzed start up to occur, however a home gardener

could wait, but why?!

The first integral ingredient to start up your aquaponic brew is ammonia. Ammonia

not only needs to be present for start up to occur it must also be present in desired levels.

Ammonia can be introduced in one of two ways, with or without fish. Ammonia is a nitrogen

and hydrogen compound (NH3) and in its ammonia state is highly toxic to fish. When converted

by the bacteria to its nitrogen state ammonia is great for plant growth and much more

tolerable by fish. However, as mentioned before, ammonia must be at certain desirable levels

for a system to cycle. An ammonia reading of less than 3.0ppm and ideally 1.0 to 1.5 ppm will

be optimal for start up with pH in the 6.8 to 7.0 range and temperatures between 62F and

72F. Below 6.8, the nitrifying bacterias reproduction will be impaired and anything above 7.0

will make the ammonia more toxic to the fish. The toxicity of the ammonia is directly related

to the temperature and higher water temps will elevate the ammonia levels quickly.

Ammonia must be monitored daily during the cycling process and a water change must

be done if readings are greater than 3.0ppm. Start out by exchanging a third of the system


water with new, non chlorinated water of similar pH and temperature to insure the least

amount of stress for the fish. Test the water and if ammonia levels are still too high, exchange

additional water until the ammonia is back into the optimal range. This may occur more than

once, especially depending on how much fish you have stocked in your system. Its not

surprising for a new colony of nitrosomonas to struggle keeping up with converting the amount

of ammonia being generated. Although you will not be feeding your fish at first, they will still

create enough ammonia. The next issue that sometimes occurs is what is called a nitrite spike.

That is due to the fact that the nitrosomonas replicate faster than the Nitrospira and now the

Nitrospira may not be able to keep up converting all of the nitrites. Nitrites are as lethal to fish

as the ammonia, so sometimes action must be taken to manage a nitrite spike.

Nitrites over 5ppm can and will kill fish. It is similar to carbon monoxide for those that

breathe air and will bind with the blood in place of oxygen and impairs the fishs ability to take

up adequate oxygen(Bernstein, 2011). Rather than diluting the system as when correcting an

ammonia spike, nitrites can be controlled by another method. The nitrosomonas are light or

UV sensitive. Simply removing the rafts and exposing the system water to UVs for a day will

reduce the nitrite levels. As soon as the nitrite levels return below 3ppm, replace the rafts.

Obviously this method works best with raft type systems as with media, there is no large

amount of water to expose. In the event the nitrites spike greater than 10ppm, , a water

change will be necessary and also you should also 'salt the fish' to help protect them from

disease or in the event a disease occurs.

Add at least one part per thousand of non-iodized pool or water softener salt. Do not

use table salt. Dissolve it completely in a bucket of water and then add it to the fish tank

however be sure to bypass the media beds and DWC troughs so that the salt is only available to

the fish. Salt cannot be added to the entire system water without damaging the plants. Do not

feed the fish until nitrite levels are below 1.0ppm and insure excellent aeration.

Salt Instructions for Treating Fish

To obtain a treatment level of 1-3ppt salt. 1gram salt/liter = 1ppt

Determine the conversion of grams of salt to ounces and pounds and convert liters to gallons

1gram = .035 ounces 1 liter = .26 gallons .035 ounces salt per .26 gallons

To figure out how much salt is needed for 1ppt in a 1000gallon tank:

1000gallons / .26 = 3846

3846 * .035 ounces = 134.61 ounces (convert ounces to lbs)

= 8.41 lbs for 1000gallons to get to 1 ppt


Add enough to raise the salt level to at least 1ppt on the first day. You will have to

closely monitor ammonia levels and do water exchanges likely each day to keep ammonia levels

in check. Monitor how much water you exchange. For instance if you replace 1/2 the tank

water, you can assume you now diluted your 1ppt to 0.5ppt with the water exchange and you

will need to add additional salt to raise the level back up. This will be the routine you will do for

several days while also observing the fish to see if there are still signs of the disease. Minimize

additional stress to the fish as much as possible during this time, ie. pH swings, temperature

swings(take this into consideration when doing water exchanges) and handling.

There are two ways to start up or cycle a system. This first way is to add fish to your

fish tank and they will immediately start introducing ammonia to the system. Even without

feeding the fish, they will still produce ammonia as all forms of fish waste even that which is

respirated out of their gills will produce ammonia, so adding fish easily adds ammonia to the

system. The difficult part of cycling with fish is waiting for the bacteria to proliferate quickly

enough to keep up with the amount of ammonia your fish are producing. If this doesnt occur,

ammonia can easily spike and produce conditions that are not safe

for your fish. The next section will cover how to actually perform

your system start up with fish and with detailed instructions for each

step of the way.

The second integral ingredient to your quick start up stew is

the bacteria, as without it, start up will occur but definitely at much

slower rates. Bacteria can be introduced a couple ways. Some type

of media or material from an existing system with established,

thriving bacteria can be added to a new system and the borrowed bacteria will begin to

colonize the new system in the presence of the ammonia. Be sure to actually use some kind of

material as opposed to just water from a system. The bacteria will be present in very low levels

in the water but remember they inhabit surfaces, so a piece of filter or media from an existing

system will work great. The other option is purchasing the nitrifying bacteria if none is

available. We use and recommend a product called ProLine Nitrifying Bacteria. ProLine will

rapidly introduce live bacteria to an aquaponic system and under peak conditions, a system

cycle can start in as little as 5 days. Just follow the instructions based upon your total volume of

375 gallons( the small size should do), insure you have less than 3ppm ammonia and add the

bacteria. Somewhere between 5 to 10 days, depending on your conditions, you should see

evidence of cycling. Cycling is considered entirely complete when nitrates are present and both

ammonia and nitrites are below 1.0ppm and can take anywhere from 4 to 6 weeks to be

complete.

ProLine Innoculant


Fishless Cycling

A second and more manageable way to cycle a new system is by introducing ammonia by

literally adding ammonia to the system instead of fish. This is considered a fishless cycle. We

have always cycled with fish but there are actually several advantages to fishless cycling. In

Sylvias book, Aquaponic Gardening, she describes this process perfectly and she also advocates

it. She says, While cycling with fish is perhaps the most straightforward of the cycling

techniques, Im not a big fan. It is very stressful on your fish because they are being subjected

to unnecessarily high levels of ammonia. They will not be feeling well, and may not come

though the process alive. All of this is stressful on you as well because you will be worried

about your fish. All very true! Not only will you be stressed about killing your fish, because you

will kill some, there is also the expense to consider, especially if something goes askew and you

have a large fish kill.

Here are some other advantages of fishless cycling as pointed out by Bernstein. Because

no fish are involved, the pH can actually go into higher ranges where the bacteria will find it

easier to proliferate. Also, the ammonia concentration can be considerably higher as well,

enabling the cycling process to transpire faster. Cycling length can be cut in half or greater.

Once the cycle is completed, the system can be stocked at once with a large amount of fish as

opposed to gradually stocking as one would with a fish cycle. Last, by you controlling the

ammonia being added to the system rather than the fish, its easier to manage the ammonia

levels and allow the bacteria time to adjust or keep up.

There are several sources of ammonia but the most common is liquid ammonia or what

is often used as a household cleaner. Use only the pure form which is 5 10% by weight and

water and has ingredients listed on the bottle. Be sure to avoid any ammonia with additives or

that foams when shaking the bottle. Ammonia can also be obtained in the crystallized form

and usually can be found through aquarium stores. Its advantage is that if found at an

aquarium store, there should be no doubt that it is safe for cycling an aquaponics system.

(Bernstein, 2011)

Here is how Sylvia instructs to do a fishless cycling.

Add the ammonia to the tank a little at a time until you obtain a reading of 2 -4ppm

Record the amount of ammonia needed to get to 2-4ppm and add the same amount

daily until nitrites appear, at least 0.5ppm. Test daily and be sure ammonia does not

reach 6ppm while waiting for the nitrites to develop. If ammonia is nearing 6ppm, stop

adding ammonia until levels resume to 2-4ppm.


Once nitrites appear, reduce ammonia additions to half. Insure nitrite levels dont

exceed 5ppm. If they do, stop adding ammonia, remove the rafts until they decline

to at least 2ppm.

Once nitrates appear, cease adding ammonia. As soon as nitrates are at least 5ppm

and both ammonia and nitrites have dropped to zero, add fish.

Whether doing a fishless or fish cycle, the plants should go into the DWC area at the same

time, as soon as nitrates appear. However, when cycling a new hybrid system with a media

bed, you can plant the media bed when you start the cycling process. Plants are capable of

taking up nitrogen during the cycling process and also the shock from transplanting when the

plants may not grow for a couple weeks can correspond to this cycling time. When cycling is

complete and nitrates are in abundance, the plants have recovered from their transplant and

are ready to take up nutrients and grow.

Cycling with Fish

If you elect to cycle your system with fish, here are the steps.

Insure there is no chlorine or chloramines present in the water. Unless you know for

certain about your water source, test for both. Ammonia will indicate the presence of

chloramines

Add 1/3rd of the recommended stocking density for your system to the fish tank

Do not feed the fish

Test ammonia

When ammonia is between 1.0-1.5ppm and certainly less than 3ppm, add either a

healthy amount of bacteria from an existing system in the form of media or a filter or

even rafts out of another DWC system or add a nitrifying bacteria per the

recommended amount

Test and record ammonia and nitrites daily

Check for dead or dying fish daily. Dead fish will off gas much ammonia as do fish that

are dying. Remove dying fish to a separate tank to monitor their condition

Monitor the ammonia levels to insure they stay in safe ranges, ie. less than 3.0ppm

o IF AMMONIA GOES ABOVE 3.0PPM!

Change out at least 1/3rd of the system water and replace with fresh

water that is similar in pH and temperature

Test the ammonia, if it was not reduced enough, exchange additional

water until reading drop


Watch nitrites. Make sure nitrites do not spike above 5.0ppm

o IF NITRITES SPIKE ABOVE 5PPM!

Remove the rafts from the DWC system for one day and test nitrites.

Replace the rafts when nitrites are back below 3ppm

Continue monitoring ammonia and nitrites and reacting as necessary. Continue to not

feed. I know it seems cruel, but they will be ok without food for a couple weeks and in

their new environment with ammonia and nitrites creeping around, they arent likely

going to be very hungry anyway.

Once nitrites stop climbing and nitrates are present, add your seedlings.

You can also begin to feed the fish

If you have thought ahead and have the next 1/3 stock of your fish in a quarantine tank,

you can now add more fish. Be sure to quarantine any new fish for at least 45 days. It

would not be good to introduce a fish disease into a newly cycled system!


Section 2

Plants, Fish, Media and Worms

Insect Control

One of the only things we do use for pest control is a product called DiPel. It is

essentially a bacterial agent that will kill insects such as caterpillars and is food and fish safe.

According to the manufacturer, Valent Biosciences, DiPel is a biological insecticide based on a

naturally occurring compound Bacillus thuringiensis, subsp. Kurstaki. DiPel contains a balanced

blend of five bacterial protein toxins and a spore, which enhance efficacy and assist in

resistance management.

The manufacturer also explains how DiPel works. DiPel must be eaten to be effective.

DiPel contains protein endotoxin crystals and living spores. Protein endotoxin is a selective

stomach poison. Spores contribute to toxicity by causing blood poisoning and providing

environmental persistence.

a) Larvae ingest DiPels crystal protein s from treated leaves.

b) Feeding stops within minutes after crystals are solubilized in the gut and gut cells are

damaged.

c) After toxin damage to gut, spores enter through gut wall and germinate rapidly in body cavity

causing blood poisoning.

d) Larvae stop feeding in as little as half an hour and die in 1-3 days.

Aphid action plan Aphids can be a tremendous problem and one that we and other ap

farmers we know struggle with. The problem that we generally see is that the wonderful

planting density that aquaponics affords is actually a drawback when it comes to insects.

Ground crops that are amply spaced out have more resistance simply because the plants are

not close together, but what do you do when we are growing at 2 or 3 times that density? We

like to call our aphid action plan a three prong approach. First of all, if aphids are discovered,

do not do nothing! They can and will quickly become an infestation.

First, use a product called Diatomaceous Earth(DE). It comes in two forms food and non

food grade but only the food grade should be used in case it contacts the food product. Line

the ground around the perimeter of your grow beds with the DE as well as the perimeter of

your greenhouse or structure. The purpose of the DE is to inhibit ants from farming the aphids.


Although this is pretty gross, ants like to suck the waste or honeydew that comes out of the

aphids and will farm or transport the aphids to the plants where the aphids can then suck the

sugar rich moisture out of the leaves of the host crops. Some ants will even milk the aphid to

get it to excrete the high sugar waste and will also defend their precious aphids from predator

insects. So the first line of defense against aphids is to eliminate the ants!

Second, purchase lady bugs from an insect supply. We get ours from Arbico Organics.

Lady bugs and their larvae will eat aphids. Other insects can be used as well such as parasitic

wasps, however some such as the wasps will leave cocoons on plant leaves and if you have a

leafy crop, this type of aphid control is not desirable.

Last, if the infestation is bad, rinse the aphids from the plants with a squirt bottle and

deliver a strong stream of water to the underside of the plant leaves to dislodge the aphids.

This is a very time consuming procedure, but in the event of a bad infestation, it is another

means to aphid defense. Once the aphids are dislodged, they will need their helper ants to get

back to the plants and again if you have eliminated the ants, the aphids cannot regain their

position.

Plant Care

Plant care involves things such as maintaining and pruning for optimal health and growth and

also being able to identify nutrient deficiencies, disease or other issues. Remove yellow leaves

and keep tomato plants well pruned. The following chart from the Aquaponic Gardening

Community will help to identify what type of deficiency your plants may have. Refer to local

gardening guides or seasonal charts from your agriculture extension university for info on when

to start different crops and varieties.

Nutrient Deficiency Chart for Plants

Nitrogen:

Leaves to show effects first: Old

Entire plant turns yellow green, and the older leaves become more yellowish than the younger.

Older leaves do not die unless deficiency is extreme.

Phosphorus:



Plant stops growing and becomes darker green or stays green.

Some species may become purple with excess anthocyanin pigments building up.

Other species do not produce excess anthocyanins and just stay green and small.

Premature leaf drop-off.

Similar to nitrogen deficiency.

Calcium:

Leaves to show effects first: New

Mild deficiency: Smaller, distorted new leaf growth. Reduced leaf tissue, with the central vein

persisting.

Leaves often cupped, rather than flat

Moderate deficiency: Often sudden bends or twisting of leaf, which is now much reduced in

size.

White streaks or white edges in new growth. Roots are stubby and twisted. Root tips may die.

Leaves of Vallisneria are strongly crinkled as though they have tried to grow and got jammed in

a small space.

Severe deficiency: New growth almost entirely white. Leaves are tiny deformed stumps.

Growing points for both shoot and root die.

Damage and die off growing points.

Yellowish leaf edges.

Magnesium:


Indicots: Yellowing of older leaves that starts from the edges inwards. The midrib may remain

green while the edges are yellowed or whitish and dying (I don't know what this deficiency

looks like in monocots like Vallisneria, but it should involve death of the older leaves.)

Yellow spots.

Potassium:


Small dead areas appear in older leaves. These can start like little pinpoints and grow. In some

species, like Ceratopteris, the older leaves stay green while the little dead spots grow. The new

leaves are reduced in size and leaf area, looking a bit 'singed'. In other species the older leaves

can turn yellow before they die, but they do not have green persisting along the major veins as

in magnesium deficiency.

Yellow areas, then withering of leave edges and tips.


Sulfur:


Similar to nitrogen deficiency

Iron:


Reduced chlorophyll in new growth. Leaves and stem are about the same shade. Growing tips

of Ceratophyllum become pinkish and then white. Egeria densa tips become greenish yellow to

yellow with the leaves small and clasped close to the stem. The new leaves of swords are

smaller with patches or broad streaks extending lengthwise that are more pale than the rest of

the leaf (in mild deficiency). In more severe deficiency in most plants chlorophyll is lacking

completely in the new growth which soon dies.

Leaves Turn Yellow.

Greenish nerves enclosing yellow leaf tissue.

First seen in fast growing plants.

Manganese:

Dead yellowish tissue between leaf nerves.

Copper:

Dead leaf tips and withered edges.

Zinc:


Yellowish areas between nerves, Starting at leaf tip and edges.

Boron:


Very similar to calcium deficiency. New growth is distorted and smaller, and then the growing

tips of both roots and shoots die. In mild deficiency in Crypts, the leaves are cupped and the

roots are shorter and distorted.

Dead shoot tips, new side shoots also die.

Molybdenum:


Yellow spots between leaf nerves, then brownish areas along edges.

Inhibited flowering


Seeding/Planting

To start seeds, first soak the Coconut Coir brick in a bucket. Place the brick of coir into

the bucket and add water to cover. Allow to expand and then use a colander or another bucket

with several holes drilled in the bottom to act as a large strainer. Mix the coco coir with

Vermiculite that can be purchased at Lowes or a hydro store and organic Vermicompost. This is

the ratio:

Coconut Coir 7 parts

Vermiculite (coarse) 2 parts

Vermicompost 1 part (optional)

Mix thoroughly and add water until the consistency is such that the coir when squeezed in

hand, sticks together almost like soil.

Once the media is mixed, fill propagation trays or net pots. Make a slight indention in

the media and depending on the seed drop anywhere from 1 to several seeds in. Label the

tray, moisten with a mist and cover with plastic being sure to tuck the plastic around the tray to

create a greenhouse effect.

Fish and Plants

Most of your day to day fish involvement will simply be feeding and observation. When you

first get your fish, they typically will not feed for at least the first few days as they recover from

the shock of being transported. However, lets assume you do a fishless cycle and have at least

half of your needed fish density in a holding or quarantine tank. As soon as your system is

cycled you can introduce both the fish and your plants. Transferring the fish into the system

tank will also be a stressful event. Netting can sometimes damage gills and just any

environmental change will be something with which they will have to acclimate.

Once the fish are comfortable in their new surroundings, begin introducing feed. Make

sure the tank covering, even if mesh is not touching the surface of the water as it can affect

feeding behavior. Measure and record the amount of feed and then broadcast it across the

top of the tank. Watch your fish. Do they feed in a ravenous frenzy or do they slowly nip at

the food? Record your observations. Also record the water and air temp. You will want to

become familiar with how much you feed at certain temperatures. If the food remains after

about 20 minutes, remove it from the tank. It will float for a couple hours or longer, but

uneaten food will eventually sink to the bottom and become aneorobic in the tank. Try to feed

at least 3 times a day.


Other day to day fish responsibilities include checking for the occasional floater. You

will soon learn two things. Bugs happen and fish die and often you dont know why on either

one! It's not surprising that occasionally you will find a dead fish. Perhaps it just had a bad

heart or weve seen what we assume to be accidental puncture wounds or maybe the males

got a little overly aggressive. If it is a dead fish occasionally, there is no need for concern, if you

start having frequent mortalities, then there is a likely a problem that you will need to

investigate.

Seeding/Seedlings

The timeframe while you are cycling is great for getting seeds started and seedlings

growing so that as soon as you are cycled (without fish) both your well developed 2 to 3 sized

seedlings and fish will be ready to go into your system. The challenge however is that for your

nursery to truly be productive its best be watered with system water that you wont readily

have yet for the first time. Fortunately though when a seedling first starts, all the nutrient it

needs for the first couple weeks of its life comes prepackaged in the seed itself. The first two

leaves or cotyledons are the first embryonic leaves of the plant. Most are called dicots as they

have two embryonic leaves and the plant utilizes nutrients available in these leaves for its early

development, however once the first true and generally third leaf develops, the plant now

requires fertilization. How you deliver fertilizer to these first batch of seedlings can be difficult

as your system is not yet cycled and generating fertilizer.

One consideration when first starting your system is the type of plants you can start and

that your system will produce well. Generally any type of aquaponic system takes some time to

mature and fruiting plants introduced early on may not fruit. We still advocate planting your

fruiting crops in the media bed, but just realize there may be some time before you actually

have mature fruiting plants even if you transplant larger plants to the bed. Leafy greens and

herbs should do well early on as these require less nutrients to grow and although higher

nitrates are generally good for leafy development, we have seen no indication that lower

nitrates dont do fine too.

As far as day to day operation when it comes to your plants, this will include seed

starting, planting, pruning, harvesting and just general observation. Typically the seed packet

and planting instructions will have recommendations for planting these types of crops to insure

a consistent harvest through the season. Use a seed planting chart to track your starts.


Fish Handling

Cultivating fish not only means handling them but also being familiar with their behavior and

habits and being able to identify when there may be an issue. Fish are easily stressed with

changes in their environment. Changes to pH, temperature, even a new tank cover can affect

fish and their typical behavior. Any time any work is done in the tank, like cleaning airstones,

its not surprising to see that affect their feeding behavior for the rest of the day. Getting to

know these little idiosyncrasies will turn you into an expert fish wrangler.

Observe your fish. Are they active, sluggish, swimming upright and able to navigate? Or

are they listing near the top of the tank and are they at the mercy of water flow and

turbulence? Fish sick from ammonia may exhibit red streaks at the mouth and gills and a

condition called pop-eye. Others can be compromised by high nitrites or very cold weather and

water temps. These fish can exhibit similar characteristics and generally feeding is depressed

and mortalities may occur. When a stressful event occurs, there is also a slight chance a

disease can occur. Diseases are rare in an aquaponic system, however just like our immunity

being compromised when we are stressed, a stressed fish can get sick.

If you think you have a sick or injured fish, remove that fish from your main tank. Its

best to place that fish in a tank completely isolated from the system, but worst case at least

transfer him to a smaller, less populated tank for easier observation. If the removed fish

recovers, simply transfer it back to the main rearing tank. Fish that die and remain at the

bottom of a densely populated large tank will emit much ammonia as they are dying and when

dead. Often, these fish can take days before surfacing and after affecting water quality.

A salt bath solution is generally recommended for suspected disease and should be

done in an isolated tank. Use non iodized pool or water softener salt and not table salt and add

1kg of salt per 1000 to 1250 liters of water. Another option when a contaminant is the

suspected culprit rather than disease is to do a system flush. This means turning on the hose

and letting the system overflow if you can. If you have city water, a flush may not be an option.

If you have a peculiar situation occurring with your fish and cannot identify the disease or

illness, contact your local ag extension agent. They usually can direct you to the agricultural

division at a state university and those that can perform the needed tests to diagnose your

problem. Be sure to not add any antibiotics or treatments to your system! Fish needing to be

treated will have to either be removed entirely from the system or the system somehow

isolated from the plants. Once the disease or contaminant is eliminated, you can reintroduce

your fish to the aquaponic system.


There has been much discussion on the forums as to the most humane way to kill a fish.

Two methods top the list but there is debate whether one is more humane than the other. One

way is to literally bonk the fish in the head with a blunt object. This is said to immediately kill

the fish and it suffers no pain. Another way is to subject the fish to an icebath. After a couple

minutes the fish becomes still in the icy water. Some do thrash around a bit upon first feeling

the ice water, so some question if this is truly the most humane way to kill fish.

Media and Worms

Worms and media, media and worms. The two pretty much go hand in hand in an aquaponic

system and being it is one very important component in an aquaponics system, we might as

well talk about them now. Ones first impression of media is that it is simply just a substitute

for soil. In one respect it is, however it actually serves many more purposes too. Soil is really

nothing more than something to stabilize a plant via its root structure and provide a reservoir

for nutrients that the plant will access again via its root structure. Therefore it is very easy to

use an inert media to mimic soil where the metabolic processes take place right in the media

The Story of Cujo the Killer Fish

One day while working in the greenhouse, the lid was off and we heard that sound that is undeniably the

plunk of a fish leaping out of the tank. We ran to the front of the greenhouse and snatched the big fish

up off the floor and threw him back into the tank. The next day we noticed that one fish was doing the

sideways dance at the top of the tank and assumed it was the escapee from the day before. Knowing

that injured or weak fish tend to be attacked, we scooped him up and put him in a small tank. Soon he

was no longer hovering around the top of the tank and it seemed he was recovering and also beginning to

eat. We felt great that we had likely saved this one Tilapia. After a little more time passed we started to

notice some really peculiar fish behavior coming from this one fish. When anyone approached the tank,

this fish would turn and face those peering at him and then charge at the side of the tank and splash

unsuspecting visitors! He was duly named Cujo the Killer Fish as he always threatened to leap out of the

tank right at anyone brave enough to peer over the side. Crazy fisha tank by himself to see what

happened. After a few days we noticed the injured fish was no longer hovering around the top of the

tank. Good! It seemed he was recovering and also beginning to eat. We felt great that we had likely

saved this one Tilapia. After a little more time passed we started to notice some really peculiar fish

behavior coming from this one fish. When anyone approached the tank, this fish would turn and face

those peering at him and then charge at the side of the tank and splash unsuspecting visitors! He was

duly named Cujo the Killer Fish as he always threatened to leap out of the tank right at anyone brave

enough to peer over the side. Crazy fish!


that then lead to nutrient composition far richer than soil can supply. There is also no nutrient

depletion or replenishment to deal with in aquaponic media bed.

In addition to the plant stability and rooting afforded in a 12 deep media bed, the

media also provides an immense amount of surface area for the nitrifying bacteria. These

bacteria will colonize any and all available surfaces in an aquaponics system, from the bottoms

of the rafts, to the liner and even on the plants roots themselves. However, a media bed has

1000s or perhaps millions of times more surface area then a DWC or raft system does alone.

Instead of one expansive flat surface to be colonized, possibly millions of small rounded pebbles

or clay pellets will offer the surface area of their entire sphere. What does this mean? It means

that a system that provides ample dark and wet surface area will accommodate excellent

bacteria levels and build an even more prolific biofilter.

Our original DWC system was a UVI derived system but did not include the use of a

biofilter. The UVI system and other DWC systems, typically have a biofilter chamber or tank

that is full of small plastic bio-balls that provide some of the same characteristics of a media

bed. These bio-balls offer additional surface area and are generally in the chain of tanks after

the solids removal system. Although these bio-balls create additional surface area in this type

of biofilter, it still lacks the one component a media bed boasts. Some solid and liquid wastes

are exported out to the media bed where both the heterotrophic bacteria and the added

worms will provide an added layer of metabolization in your system. Without this combined

media bed/DWC system, all of the solids would have to be removed and left to break down and

compost externally where they will not benefit the system at all.

Media beds also provide the perfect habitat for a thriving, composting red worm colony.

Some wonder how the worms survive in such a wet environment, but the flood and drain

action provides just the right mixture of wet and dry and oxygenated water. The worms can

move around easily in a course media such as gravel as the interstitial space between the rock

allows for plenty of movement and worm activity. The worms are important and reduce the

volume of the solid matter by more than 60% and

while doing that they create vermicompost that is

then released into the water column for the plants

to uptake.

Worms are an integral part of your media

bed. Sylvia Bernstein recommends at least a pound

of worms which is typically about a 1000 worms for

every 20 cubic feet. That translates into


approximately 1lb of worms for a HomeHybrid system. Although this seems like a lot of worms,

the population then becomes entirely dependent on the food supply. The population will

expand or contract depending on what is happening with the delivery of solids to the beds, but

says you can never basically have too many worms.

Worms also deliver other benefits to the aquaponic system. Because they are

heterotrophs, they consume the organic matter that is comprised of the fish waste, any plant

waste or root waste material. They are the perfect complement to the non-organic eating

autotrophs that feed on the inorganic matter such as the ammonia and nitrites. The worms

produce a highly concentrated fertilizer called vermicompost and when steeped in highly

oxygenated water, ie. an aquaponics system, they provide the needed nutrients.

To plant in your media bed, do so just as you would in a soil garden. Simply displace the

rock or media, place the roots well down in the gravel and cover over. Be sure to get the roots

low enough to insure the water will reach them as the bed floods. We prefer to wear gardening

gloves when planting in the media bed too. Direct seeding in the media bed is an option as

well as the wicking action and moisture present will work to germinate seeds.


Section 3

Components and Construction

Auto Siphons

One component we will review is the auto siphon. Auto siphons work well with this

media bed/DWC hybrid design because it complements the constant flow feature of using

gravity flow as opposed to a cycled on and off timed pump flow. With an auto siphon, the bed

constantly fills as the water is delivered non stop from the 3 media bed outflow pipe. As the

water level fills in the media bed, it also fills the area inside the siphon until the level is deep

enough to fill the pipe that is inside the siphon. Once the water starts spilling over into the the

pipe in the center of the siphon, a low pressure area is created within the siphon and the

siphoning action is triggered. When this occurs, the siphon rapidly draws the water from the

bed and the bed drains to the sump below. When nearly all water has emptied, air enters the

siphon and the low pressure that created the siphoning action is lost and the siphon ceases

firing or draining.

A siphon has several components that fit

together. A 1 FIPT x FIPT (threaded on both top

and bottom) bulkhead is screwed into the bottom

floor of the medium bed and from there a 1 MIP

fitting is threaded into the bulkhead and a 1stand

pipe is inserted into the slip side of the MIP fitting

but not glued. At the top of this stand pipe is a

fitting that can create a funnel like shape at the top

of the standpipe. This helps aid in the action that

creates the low pressure and triggers the siphon. Rather than using a fitting however, we used

the bell housing side of a 1 irrigation pipe so the funnel was essentially built in. Below the

deck and threaded into the bottom of the bulkhead is the return pipe. Thread a threaded and

slip 90 into the bulkhead and extend a short piece of 1 out of the slip side of the 90. Do not

glue. Now back on the top side of the siphon, a larger pipe called the bell sits over the stand

pipe. The 2 bell should be at least 1 or 2 higher than the standpipe with a glued cap. The last

component is the media guard which is a 4 section of PVC with either holes or slits to prevent

media from getting into the siphon.

Siphon from The Aquaponics Source


To best understand how the siphon fires and triggers, we will refer to Sylvia Bernsteins

excellent explanation in her book Aquaponic Gardening. On page 102, as Sylvia describes the

configuration of the bell, she explains how the siphon action occurs. She says:

The middle piece is called the bell. It is a pipe long enough to fit over the stand pipe

with an inch or two to spare. The top is sealed and air tight, usually with a pipe cap.

The bottom of the pipe sits on the floor of the grow bed and has several notches(or

holes) about half to one inch above the bed floor to allow water from the grow bed to

fill the bell as the water rises in the grow bed. As the water rises in the grow bed, the

notches(or holes) in the bell will be covered by water. This will create an airtight seal

within the bell. When the water rises to the top of the stand pipe, water will begin to

spill into the funnel and down into the stand pipe. When there is sufficient flow into the

stand pipe, the downward water flow will block the air from coming into the bell

through the bottom of the stand pipe. This will facilitate the creation of the low-

pressure area within the bell. When almost all of the water has drained from the grow

bed, the water level will reach the notches (or holes) in the bottom of the bell. At this

point, air will enter the bell through the notches, the pressure win the bell will equalize

with the atmospheric pressure and the siphoning action should stop.

The rate of water entering the bed is critical as it insures that the water coming in is slower

than the water is leaving the bed. Otherwise if the water is entering too quickly, the siphon

cannot break and the bed will never fill and the flood and drain action will not occur. Likewise if

there is not enough water coming in, the siphon will not trigger. When a siphon is not breaking,

turn the flow down just slightly until the siphon breaks. If the siphon cannot engage because

the water is not filling up quickly enough to start the siphon, you will likely need a larger pump.

Although according to Sylvia, an inner sleeve or smaller pipe can be inserted into the stand pipe

or a longer extension can be added to the 90 below the siphon to help the siphoning action to

engage(Bernstein, 2011) when there is insufficient flow.

Plumbing it All Together

Always use DWV or Schedule 40 Drain Waste Vent pipe which is used for potable water and is

safe for growing both fish and plants. Whenever possible use DWV and sweeps rather than

90s. These have broader turns and are easier on flow. Always, always, always use primer

before gluing the pipe. This etches the surface of the slick pipe and creates what is called a


profile that the glue can adhere to. Weve heard some say that they have glued up PVC without

priming, however for a water tight, steadfast joint, be sure to always use primer.

The System Build

Weve developed the perfect marriage between Deep Water Culture(DWC) and media bed

growing for the ultimate in aquaponic versatility for

Documents

By AP Guide Master File 2514