Gardening with aquaponics is a passion for me. For almost 2 years Ive visited my fish first thing in the morning, and its the last thing I do before bed. I enjoy the science and systems that sustain this marvelous symbiotic garden with biological interactions that continue to flourish and amaze me.
Ill warn you that a lot of what you will find on the internet is hype and rubbish. For example growing lettuce at four times the normal yield is just not going to happen. Aquaponics is not going to feed the world, and its not as easy as many make it look, and unless you are a top notch salesman you will not grow rich selling produce, and fish or aquaponic systems. Beware of people selling anything related to aquaponics. There are no secrets in aquaponics.
Why do you want to grow with aquaponics? Chances are you either want to
1. save money on food,
2. avoid kneeling,
3. reduce your water consumption,
4. be sure you are eating healthy organic food,
5. help reduce the depletion of fossil fuel and lower the carbon foot print of your existence.
Ill warn you that a lot of what you will find on the internet is hype and rubbish. For example growing lettuce at four times the normal yield is just not going to happen. Aquaponics is not going to feed the world, and its not as easy as many make it look, and unless you are a top notch salesman you will not grow rich selling produce, and fish or aquaponic systems. Beware of people selling anything related to aquaponics. There are no secrets in aquaponics.
Why do you want to grow with aquaponics? Chances are you either want to
1. save money on food,
2. avoid kneeling,
3. reduce your water consumption,
4. be sure you are eating healthy organic food,
5. help reduce the depletion of fossil fuel and lower the carbon foot print of your existence.
Maybe its all of these, but "traditional aquaponics" is not a sustainable method. To be fair, I cant think of any method of farming that provides animal protein in a sustainable fashion, especially if we are not able to allow the animal to free roam and forage for their own food. After you add up all the energy involved with aquaponics it still uses more energy to pump water than the caloric energy it grows. But aquaponics is a move in the right direction, and it does save transportation energy. In ideal locations aquaponics could produce 30,000 lbs of fish per acre per year compared to less than 100 lbs for cattle, but dont forget the fossil fuel required to make that happen. For more on that [CLICK HERE].
This is why I strive to design low energy systems, and grow with the seasons. These integrated systems qualify as Permaculture, and I will show you how to accomplish every one of the goal on that list! My first rule is dont fight Mother Nature. She can be generous if you work with her.
Traditional aquaponics may never grow enough food to get back what you invest, but you will save a lot of water, know first hand how safe your food is, and if you design it with raised beds or vertical towers you will not have to get down on your knees.
Growing a garden is a challenge, at least it was to me. Aquaponics is not any easier, and often times more difficult than soil based gardening. I dont consider myself an expert, just experienced. I hope I can help you get you off to a good start because it can provide a great deal of enjoyment.
Here is a list of topics I will cover
Sustainability
Water Quality
Carbonates, pH, water chemistry and nutrients
Iron
Media beds
Media
Radial Filters
Cycling & Nitrification
The System Build
Concrete
Wood Tanks
International Bulk Containers (IBC)
Drums
Bell Siphons
Timed Fill and Drain
Old School Fill & Drain
Air Pumps
Airlift Pumps
Electric Pumps
CHOP 1 vs CHOP 2
Level Systems
Flow Rate
Fish
Compassionate Killing of Fish
Fish Food
Breeding Fish
Level Systems
Media Beds
Wicking beds
Earthan Beds
Wicking Pots
Deep Water Culture (DWC)
NFT (Nutrient Film Technech)
Vertical Towers
Bioponics
Plants
Green Houses
Rocket Mass Stoves
Evaporative Coolers
Floors
Pipe sizes
Insulation
Lights
Heating
Starting from Seeds
Keep a Log
Sea Salt
Pest Control
Site & Experts to follow
This is why I strive to design low energy systems, and grow with the seasons. These integrated systems qualify as Permaculture, and I will show you how to accomplish every one of the goal on that list! My first rule is dont fight Mother Nature. She can be generous if you work with her.
Traditional aquaponics may never grow enough food to get back what you invest, but you will save a lot of water, know first hand how safe your food is, and if you design it with raised beds or vertical towers you will not have to get down on your knees.
Growing a garden is a challenge, at least it was to me. Aquaponics is not any easier, and often times more difficult than soil based gardening. I dont consider myself an expert, just experienced. I hope I can help you get you off to a good start because it can provide a great deal of enjoyment.
Here is a list of topics I will cover
Sustainability
Water Quality
Carbonates, pH, water chemistry and nutrients
Iron
Media beds
Media
Radial Filters
Cycling & Nitrification
The System Build
Concrete
Wood Tanks
International Bulk Containers (IBC)
Drums
Bell Siphons
Timed Fill and Drain
Old School Fill & Drain
Air Pumps
Airlift Pumps
Electric Pumps
CHOP 1 vs CHOP 2
Level Systems
Flow Rate
Fish
Compassionate Killing of Fish
Fish Food
Breeding Fish
Level Systems
Media Beds
Wicking beds
Earthan Beds
Wicking Pots
Deep Water Culture (DWC)
NFT (Nutrient Film Technech)
Vertical Towers
Bioponics
Plants
Green Houses
Rocket Mass Stoves
Evaporative Coolers
Floors
Pipe sizes
Insulation
Lights
Heating
Starting from Seeds
Keep a Log
Sea Salt
Pest Control
Site & Experts to follow
I want to talk about the many questions I had as a newbie aquapon, and discuss some brilliant ways to improve traditional aquaponics.
Questions will always come up when designing your first system. I will attempt to remember what mine were, and anticipate what yours are too. I also want to mention an alternative to aquaponics with fish. Bioponics is aquaponics without fish. It uses other sources of nitrogen there by avoiding many problems and expenses involved with raising fish. If you do not eat a lot of fish I encourage you to go this route.
Water Quality
There are often concerns about detritus in the media and water. Let me first say, worms in all of your media beds are very beneficial whether it be Earthan, Wicking, or LECA (Lightweight Expanded Clay Aggregate). They consume dead roots, uneaten food, and with the help of bacteria in their guts, make minerals available to the plants through a process called chelation. They help keep the media clear of excess gunk, and feed the plants in the process. Worms (Eisenia Foetida – the Red Wiggler, Californian red worm) to be exact should be in your system. You can even feed them to your fish.
Carbonates are bad for beginning systems because they remove a level of control for beginning systems (i.e. before your nitrification efficiency is up). Your related acidification is really weak and carbonates can overwhelm the process, leading to chronically high pH. (i.e. 8+) which limits nutrient availability and makes it difficult to stabilize your system where it should be (below 7 for commercial systems). - Nate Storey (Bright Agrotech)
pH and water chemistry and nutrients:
If the pH gets too high you will need to lower with acid. Buffing from the carbonates in your grow media, and local water supply may make the pH difficult to adjust.
Questions will always come up when designing your first system. I will attempt to remember what mine were, and anticipate what yours are too. I also want to mention an alternative to aquaponics with fish. Bioponics is aquaponics without fish. It uses other sources of nitrogen there by avoiding many problems and expenses involved with raising fish. If you do not eat a lot of fish I encourage you to go this route.
Water Quality
There are often concerns about detritus in the media and water. Let me first say, worms in all of your media beds are very beneficial whether it be Earthan, Wicking, or LECA (Lightweight Expanded Clay Aggregate). They consume dead roots, uneaten food, and with the help of bacteria in their guts, make minerals available to the plants through a process called chelation. They help keep the media clear of excess gunk, and feed the plants in the process. Worms (Eisenia Foetida – the Red Wiggler, Californian red worm) to be exact should be in your system. You can even feed them to your fish.
Carbonates are bad for beginning systems because they remove a level of control for beginning systems (i.e. before your nitrification efficiency is up). Your related acidification is really weak and carbonates can overwhelm the process, leading to chronically high pH. (i.e. 8+) which limits nutrient availability and makes it difficult to stabilize your system where it should be (below 7 for commercial systems). - Nate Storey (Bright Agrotech)
pH and water chemistry and nutrients:
If the pH gets too high you will need to lower with acid. Buffing from the carbonates in your grow media, and local water supply may make the pH difficult to adjust.
http://www.chemguide.co.uk/physical/acidbaseeqia/phcurves.html
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| At the point at where the buffer is overcome any further amount of acid will cause a drastic pH change |
GO SLOW. As you add Hydrochloric acid the pH will drop, and then bounce back. Dont get frustrated and dump extra in. You will reach a point where it kicks in and then a little goes a long way. It is possible to kill your nitrifying bacteria if you go too low.
Ive never had a problem with low pH, but the same applies. Add a threshold level of HCl (Hydrochloric Acid) or KOH (Potassium Hydroxide) and then test pH a day later and adjust with a smaller adjustment dose. This is actually safer than calculating because it allows other variables to impact pH over the course of 24 hrs
Iron is almost always lacking in aquaponic systems. The form of iron is very important. The three common chelated forms (iron-EDDHA, DTPA and EDTA) differ in their ability to keep iron soluble and available to plants as the pH increases. Between a pH of 4.0 to 5.5, any form of iron will work (including iron sulfate) at supplying iron to the plant. However, as the pH increases above 7.0, only the iron from Fe-EDDHA will have high solubility.
Iron-EDDHA 4 >< 9 pH
Iron-DTPA 4 >< 6.5 pH
Iron-EDTA 4 >< 5.5 pH
Research has shown that the ranking of iron forms from most effective to least effective at supplying iron at high media pH is Fe-EDDHA Iron-DTPA > Iron-EDTA > Iron sulfate. If iron is applied in a form that is not soluble because of high media pH, then most of the nutrient will not be available to plants until media pH is lowered.
In general the best products will say EDDHA (Sequestrene 138) because they work over the widest range of pH. Sequestrene 330 is ETPA and it is more affordable. Use Sequestrene 138 only if your media is alkaline and calcareous If your soil/media is very acidic I would still use ETPA Sequestrene 330 rather than EDTA. ETPA (Sequestrene 330) is the best all around iron to buy if your are maintaining your system between 6.2 and 6.5. Iron Sulfate can be used as a foliar application in aquaponics, and may not be terribly detrimental to your fish, but I would not use it when there are better choices.
Sequestrene is what I use and its widely available on the internet, but others are good too. Sequestrene 138 may has been reported to turn the water red but Ive only used 330 so I dont know for sure if that is true or how much of a problem it is.
Ive never had a problem with low pH, but the same applies. Add a threshold level of HCl (Hydrochloric Acid) or KOH (Potassium Hydroxide) and then test pH a day later and adjust with a smaller adjustment dose. This is actually safer than calculating because it allows other variables to impact pH over the course of 24 hrs
Iron is almost always lacking in aquaponic systems. The form of iron is very important. The three common chelated forms (iron-EDDHA, DTPA and EDTA) differ in their ability to keep iron soluble and available to plants as the pH increases. Between a pH of 4.0 to 5.5, any form of iron will work (including iron sulfate) at supplying iron to the plant. However, as the pH increases above 7.0, only the iron from Fe-EDDHA will have high solubility.
Iron-EDDHA 4 >< 9 pH
Iron-DTPA 4 >< 6.5 pH
Iron-EDTA 4 >< 5.5 pH
Research has shown that the ranking of iron forms from most effective to least effective at supplying iron at high media pH is Fe-EDDHA Iron-DTPA > Iron-EDTA > Iron sulfate. If iron is applied in a form that is not soluble because of high media pH, then most of the nutrient will not be available to plants until media pH is lowered.
In general the best products will say EDDHA (Sequestrene 138) because they work over the widest range of pH. Sequestrene 330 is ETPA and it is more affordable. Use Sequestrene 138 only if your media is alkaline and calcareous If your soil/media is very acidic I would still use ETPA Sequestrene 330 rather than EDTA. ETPA (Sequestrene 330) is the best all around iron to buy if your are maintaining your system between 6.2 and 6.5. Iron Sulfate can be used as a foliar application in aquaponics, and may not be terribly detrimental to your fish, but I would not use it when there are better choices.
Sequestrene is what I use and its widely available on the internet, but others are good too. Sequestrene 138 may has been reported to turn the water red but Ive only used 330 so I dont know for sure if that is true or how much of a problem it is.
Media beds clean, and filter the water, but that is not their primary purpose. In fact even a bio-ponic system (aquaponic system without fish) will accumulate muck in the media. To a certain extent that is what you want for good nitrification and as your system matures it will continue to improve. What you dont want is food and poo clogging the media, and creating anaerobic spots. Therefore we remove the detritus from the water with a radial filter. The main purpose of media is to provide nitrification, and as luck would have it, media beds provide a place to grow plants. People from the aquaculture world often miss this last point and try to incorporate a very efficient Fluidized Biological Filters as well.
Media provides filtration, a place for plants and most importantly nitrification.
BSA (Biological Surface Area) depends upon the SSA (Specific Surface Area) of the media. The higher the BSA the better because the bacteria which provides nitrification likes to grow on surfaces. Most IBC systems average about 25 ft2 surface area per pound of fish. 100 or more sq ft per pound would be really great for the fish, but somewhere in this range is good.
The surface area of the media where the bacteria grow increases with porous media. Kaldness is used in aquariums because it has been designed to provide a very high SSA of about 244 ft2/ft3, while providing good flow. Flow is the crux, because even though media such as sand has a high SSA of about 270 ft2/ft3. and a void ratio of about 40% the flow rate is too slow.
There is a wide range of media with good flow and high SSA, but some to stay away from are any rock that will change the pH such as marble or lime stone and GrowStones in apquaponic systems because they are made of glass which will leach into the fish tank and harm your fish. They would be great in a bioponic system though.
The best products are LECA (Lightweight Expanded Clay Aggregate), Expanded Shale or Bio-Char if you are able to afford, and obtain them. For the rest of us Lava Rock is my preference because it is cheap, porous, not too heavy and contain a lot of minerals for the plants. Microporous solids called zeolites form in volcanic rocks. According to Russel Water Gardens - Lava Rock has an SSA of 86 ft2/ft3 and a bed porosity of 20%
For comparison I found this reference
gravel (40–70 mm,speci?c surface area of 700 m 2 / m 3 and bed porosity of 0.4)and a LECA with the commercial name of Filtralite NR(4–8 mm, speci?c surface area of 1250 m 2 / m 3 and bedporosity of 0.45).
I converted that to inches and feet.
1.5-2.5 inch gravel has an SSA of 213 ft2/ft3 and bed porosity of 40%
1/8–3/8 inch LECA has an SSA of 318 ft2/ft3 and bed porosity of 45%).
Some of these figures do not seem to jive... It may be that the 2 gravel was not ordinary drain rock.
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| Nate Storie showing specifications for Sand, Pea Gravel, 3/4" Rock, 1" River Rock and his Zip Tower Media |
http://youtu.be/EKGiXoJMLbo
Radial Filters are inexpensive to build, extremely efficient, and offer the side benefit of capturing fry before they are eaten. To grow healthy plants we must keep the roots clean, and the radial filter will do a better job. There are many versions of radial filters on the internet, but the principal is pretty basic, and easy to understand. A radial filter will remove most of the detritus by slowing the water down, and allowing it to settle to the bottom of the radial filter, thus keeping your DWC raft beds, and media beds as clean as they need to be.
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| Basic radial filter |
There have been quite a few other types of filters tested, but any attempt to use filter pads will create a lot of extra work, and jeopardize the clear flow of water if you forget to clean it. Depending on the size of your filter you will be married to that chore more often than you like.
I only do this when my fish have babies, but occasionally I will place a filter inside my radial filter on the exit pipe in order to save the fry that get sucked in. I can then move them to a safe tank until they grow a bit larger.
I only do this when my fish have babies, but occasionally I will place a filter inside my radial filter on the exit pipe in order to save the fry that get sucked in. I can then move them to a safe tank until they grow a bit larger.
Cycling
One of the biggest blunders newbies make is to buy fish before the system is cycled. Cycling involves growing bacterial (nitrification) which will naturally find their way into a aquaponic system. There is no need to buy this bacteria, and every product I have ever used did absolutely nothing. This includes products claiming to have several bacteria strains, and those claiming to have special enzymes. Nitrification takes a minimum of three weeks, and as your system ages this process will mature and get even better.
There is only one way to speed the process. You can obtain a fresh bucket of media from an established system and add it to yours. Water from an established system will not work. To feed and grow the nitrifying bacteria simply add enough urine to maintain the ammonia at about 0.5 - 1.00 ppm more or less, and let the water flow through the media and it will begin to grow.
There is possibly one other way to quickly establish nitrification, but I have never tried this.
Nitrifying bacteria live on surfaces therefore a high BSA is good. Nitrification is a process where bacteria convert ammonia to nitrite and other bacteria convert nitrite to nitrate. This is a two-step oxidation process of ammonium (NH4+ or ammonia NH3) to nitrite (NO2-) then to nitrate (NO3-) . During the cycling process do not adjust your pH unless it falls below pH 7. The bacteria prefer a higher pH. The pH can be adjusted later when the bacteria have become established. It is this nitrification process that removes the ammonia and nitrites from the water and creates a clean healthy environment for your fish. Without it you will be doing several water changes per day of burying dead fish.
Nitrogen is a key component of aquaponics. We add protein in the form of fish food and that breaks down into nitrogen for our plants. For most of us this is all we need to know, but if you wish to crunch numbers and maximize the use of nitrogen then I suggest Commercial System Design – Nitrogen Budget. Paul Van der Wolf explains the entire cycle in depth.
The System Build
Your first system will probably be done as inexpensively as possible, and you may be temped to try some of your own ideas. I can tell you from experience that your tanks need to be sturdy, thin enough to accept a Uniseal or bulkhead, and of a material that will not rot from constant exposure to water which I guarantee you will spill plenty.
Concrete may seem like a good choice, but only if it is sealed. The problem with concrete is that it will affect the pH and if you continually force the pH down to an acceptable level the concrete will also weaken and crumble. There are ways to seal it with pool paint or wax, but its is probably better the just avoid it.
Wood Tanks will rot if water accidentally gets under the liner. I have successfully [built wood tanks using fiberglass], but in the end this was more expensive than a good solid agriculture stock tank which can generally be picked up for about $1/gallon.
. Wood Tanks will rot if water accidentally gets under the liner. I have successfully [built wood tanks using fiberglass], but in the end this was more expensive than a good solid agriculture stock tank which can generally be picked up for about $1/gallon.
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| These bunk feeders make good DWC Raft beds and the stock tanks are perfect for fish tanks |
International Bulk Containers (IBC) and plastic drums also make very good tanks, and the size is appropriate to most backyard systems. But I like a fish tank that I can reach my hand to the bottom of so you may want to cut your container down just a little.
Drums are often free, so it is an ideal way to start. Some people like them well enough to stay with them. I like the way Justin has built his grow bed using 1/2 drums because there is no frame below the drums, but I would have added a support leg in the center or used 2x12. By the way a barrel has a removable lid a drum has two bungs.
Drums are often free, so it is an ideal way to start. Some people like them well enough to stay with them. I like the way Justin has built his grow bed using 1/2 drums because there is no frame below the drums, but I would have added a support leg in the center or used 2x12. By the way a barrel has a removable lid a drum has two bungs.
Bell Siphons work while the flow remains within the parameters they were designed for, and as soon as something changes they will fail. As much as I enjoy listening to a bell siphon cycle through its phases; and even though Im the guy who came up with the idea to use a small reservoir at the end of a breather tube, I will never use another bell siphon on any system I build. The reservoir helps, but its a Band-aid fix. Why bother with a bell siphon when there are better solutions.
Timed Fill and Drain are a better choice and they conserve energy. Running a 100W pump 24/7 uses 2.4KW per day 365 days a year. A 15 minutes on 4 hours off cycle consumes 16 times less power than a continuous run bell siphon system! I do not believe turning a pump on and off shortens the life of a pump, but everyone can have an opinion.
Media beds traditionally use a Bell Siphon, but a Timed Fill and Drain system will use less energy and run with far fewer problems.
Timed Fill and Drain systems use a small weep hole which allows the media beds to drain more slowly than they are filled. A stand pipe allows any excess water to overflow back into the sump tank until a timer turns the pump off. The beds are filled several times a day, and when the pump shuts off, the water weeps out and drains the media bed.
Timed Fill and Drain are a better choice and they conserve energy. Running a 100W pump 24/7 uses 2.4KW per day 365 days a year. A 15 minutes on 4 hours off cycle consumes 16 times less power than a continuous run bell siphon system! I do not believe turning a pump on and off shortens the life of a pump, but everyone can have an opinion.
Media beds traditionally use a Bell Siphon, but a Timed Fill and Drain system will use less energy and run with far fewer problems.
Timed Fill and Drain systems use a small weep hole which allows the media beds to drain more slowly than they are filled. A stand pipe allows any excess water to overflow back into the sump tank until a timer turns the pump off. The beds are filled several times a day, and when the pump shuts off, the water weeps out and drains the media bed.
Old School Fill & Drain
I dont know if this siphon valve has a name or how well it works, but I first saw it in Travis Hugheys Barrel-Ponic Manual. It works by pulling a toilet flapper with the weight of a 2 litter bottle. Just giving you all the options.
Air Pumps
Im running my air pump to 9 air stones and moving over 1000 gpm with 2 airlifts. Im using all the air (200 lpm) my Eco Plus 7 compressor can deliver. It runs at 93W wide open and 51W when closed.
The specs say an Eco Plus 7 compressor is rated at 200 lpm 5.1 psi and 280W. I believe the 280W rating refers to the maximum heat dissipation the motor coils can endure. Ive rebuilt Active Aqua air pumps and Ive looked inside this Eco Plus 7 and found the Active Aqua to have less space within the enclosure. After I could no longer rebuild my Active Aqua I bought the Eco Plus. My feeling is that Eco Plus has created a larger cooling area that allows the pump to operate much cooler and last longer. I could not pick my Active Aqua 70 lpm up with bare hands whereas the Eco Plus 200 lpm is only warm.
Air Pumps
Im running my air pump to 9 air stones and moving over 1000 gpm with 2 airlifts. Im using all the air (200 lpm) my Eco Plus 7 compressor can deliver. It runs at 93W wide open and 51W when closed.
The specs say an Eco Plus 7 compressor is rated at 200 lpm 5.1 psi and 280W. I believe the 280W rating refers to the maximum heat dissipation the motor coils can endure. Ive rebuilt Active Aqua air pumps and Ive looked inside this Eco Plus 7 and found the Active Aqua to have less space within the enclosure. After I could no longer rebuild my Active Aqua I bought the Eco Plus. My feeling is that Eco Plus has created a larger cooling area that allows the pump to operate much cooler and last longer. I could not pick my Active Aqua 70 lpm up with bare hands whereas the Eco Plus 200 lpm is only warm.
Ive done a similar test with my Ametek Rotron EG DR083 regenerative blower and found that restricting the outflow increases the Wattage, contrary to the compressor. The regenerative blower is great for air stones where the depth is usually pretty shallow. It delivers 521 liters per minute and uses just 118W, but the compressors advantage is the ability to deliver 5.1 psi. The regenerative blower has only 0.867 psi. So the regenerative blower does not work well for airlift pumps but it blows a hell of a lot of air to air stones!
Airlift Pumps
Air stones are highly recommended throughout any system and since we are running an air pump why not utilize it for pumping water too? Thats right airlift pumps will move large quantities of water on less power, and aerate the water while doing so.
One of the really nice things about airlift pumps is the way they can pass solids without clogging. They are in my opinion far more reliable than centrifugal pumps, and a whole lot less expensive. My airlift can be built for less then $10 and it delivers over 1000gph.
Electric Pumps - If you purchase an electric pump there are some considerations. To keep this paper short (lol) Ill insert a [Link Here]
CHOP 1 vs CHOP 2
CHOP (Constant Height One Pump) Traditional Aquaponics uses either a CHOP 1 or a CHOP 2 design. The water level in the fish tank is always a constant height and one pump delivers water to the fish tank which overflows into the media beds and then back to the sump tank. Chop 2 differs by one pump delivering water to both the fish tank and the media beds. These each return water back to the sump tank. The advantage of CHOP 1 is greater flow through the fish tank. The advantage of CHOP 2 is the ability to isolate the media beds and the fish tank. These traditional systems aerate the water by drawing air down through the media each time the water level fills and drains.
One of the really nice things about airlift pumps is the way they can pass solids without clogging. They are in my opinion far more reliable than centrifugal pumps, and a whole lot less expensive. My airlift can be built for less then $10 and it delivers over 1000gph.
Electric Pumps - If you purchase an electric pump there are some considerations. To keep this paper short (lol) Ill insert a [Link Here]
CHOP 1 vs CHOP 2
CHOP (Constant Height One Pump) Traditional Aquaponics uses either a CHOP 1 or a CHOP 2 design. The water level in the fish tank is always a constant height and one pump delivers water to the fish tank which overflows into the media beds and then back to the sump tank. Chop 2 differs by one pump delivering water to both the fish tank and the media beds. These each return water back to the sump tank. The advantage of CHOP 1 is greater flow through the fish tank. The advantage of CHOP 2 is the ability to isolate the media beds and the fish tank. These traditional systems aerate the water by drawing air down through the media each time the water level fills and drains.
Level Systems
There seems to be some misconception that fill and drain action is required for good aeration. This is simply not true. There are several methods to aerate water.
Air stones, with an air pump are generally used in any type of aquaponic system I highly recommend many air stones throughout the system, and air lift pumps definitely ensure good aeration.
Level systems do not waste energy lifting water from a sump tank. Instead the water is simply pushed along through the system, remaining the same height from one section to the next. The air lift pump, and air stones provide all the aeration necessary for good healthy roots.
This of course does leave the roots sitting in water in the media beds, but so do raft systems. There may be a few plants that dont appreciate constantly wet roots, but most do fine. Media beds have been included in every successful aquaponics system since day one, but a new concept has evolved which integrates wicking beds with aquaponics. Its called Earthan Beds, and Ill tell you more about that later.
Flow Rate - Kieth Tatjana recommends twice per hour, but no more. The Aquaponic Gardening Community site recommends once per hour. So if you have a 100 gallon fish tank you should pump 100 to 200 gallons per hour. These rules of thumb are good enough, but if you are designing a commercial system then I would refer you to "Why Flow Rates are Critical in Aquaculture" written by Paul Van der Werf.
Fish are such a wide topic. My advice is grow what you like to eat, or grow what you like to look at, but dont grow what does not belong in your neck of the woods.
Tilapia in Maine is going to require heating the system, and take it from someone who has been there, it gets expensive. Catfish, are a good all around fish, but even though they can survive, they will stop growing during the cold days of winter. If you live in Florida or Hawaii you might like to grow tilapia, but even in Florida the winter will require some heat.
The nice thing about Tilapia is they grow pretty quick, they are hardy, and they reproduce well, but catfish kept in a warm water tank will also fulfill these qualities. If you live in a very warm climate, go for it. But most of us will be better off with a local fish that is acclimated to our area. Perch, Blue Gil and even trout are being raised in cool climates.
Larger systems are more stable, but start small. A 100 gallon tank with about 16 lbs of fish and 16 sq ft of garden is a very nice system. You can expand the grow bed on that system a little, and stock the fish a little heavier, but for starters its best to keep a light fish load.
Breeding Fish - I have found that fish will breed without my intervention. But some like to identify the males and females and place one male among several females. Sexing fish is not easy, but Robb Nash has a good method in his link. Once the fry are available it is a good idea to separate them so they will not be eaten.
Compassionate Killing of Fish
Fish are such a wide topic. My advice is grow what you like to eat, or grow what you like to look at, but dont grow what does not belong in your neck of the woods.
Tilapia in Maine is going to require heating the system, and take it from someone who has been there, it gets expensive. Catfish, are a good all around fish, but even though they can survive, they will stop growing during the cold days of winter. If you live in Florida or Hawaii you might like to grow tilapia, but even in Florida the winter will require some heat.
The nice thing about Tilapia is they grow pretty quick, they are hardy, and they reproduce well, but catfish kept in a warm water tank will also fulfill these qualities. If you live in a very warm climate, go for it. But most of us will be better off with a local fish that is acclimated to our area. Perch, Blue Gil and even trout are being raised in cool climates.
Larger systems are more stable, but start small. A 100 gallon tank with about 16 lbs of fish and 16 sq ft of garden is a very nice system. You can expand the grow bed on that system a little, and stock the fish a little heavier, but for starters its best to keep a light fish load.
Breeding Fish - I have found that fish will breed without my intervention. But some like to identify the males and females and place one male among several females. Sexing fish is not easy, but Robb Nash has a good method in his link. Once the fry are available it is a good idea to separate them so they will not be eaten.
Compassionate Killing of Fish
Inhumane and totally unacceptable slaughter methods, that can take a long time for
fish to lose consciousness and die, should be prohibited urgently. These include
suffocating fish in air or on ice, bleeding to death without pre-stunning, and the use of
carbon dioxide for stunning.
Only slaughter methods that cause an instant death or render the fish instantly
insensible to pain until dead should be permitted. These include percussive stunning
techniques whereby fish are rendered instantly unconscious when carried out
efficiently.
I use a 1" dowel about 16" long to club my fish. The easiest way Ive found is to hold the fish in the net so that they dont slide out of your grasp. Wait a moment until they settle down and make one swift blow to the top of the head. Death is instantaneous. There is no suffering, no blood, its just a good clean kill.
Fish Food can be a major expense if you dont find a good source. I buy mine at Tractor Supply where I get 50lbs for $18.00. The important thing is to look for about 32% or better protein. For your fry you may wish to buy a more expensive product with higher protein. Some foods will leave a lot of detritus so you may want to experiment. How much and how often you feed your fish depends on temperature. They will not eat as much when cold. Under ideal conditions you might expect to feed your fish about 1.2% of their body weight. I like to watch them feed and if
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