Aquaculture is the raising of fish (in most cases a food fish) as the primary “Crop” The water used in this system will rapidly become out of balance for the fish ie., filled with fish waste… This waste water is then purged often on an ongoing basis in order to keep the water clean enough to sustain the numbers of fish being raised. This waste water is “Nutrient Rich” in that it is filled with fish waste which is a wonderful fertalizer… This throws the local water way’s ecosystem out of balance as it tries to cope with the excess nutrients. This typically causes an algae bloom that decreases the available oxygen in the water and causes massive fish die offs due to them suffocating in the water that would otherwise sustain them. If the system is able to cope with the excess nutrients, these nutrients flow out through the natural waterways to a local lake or out to the ocean. This is why we are seeing a growth in the total area affected in the Gulf of Mexico every year due to the massive algae blooms, this has been recently identified as being caused by nutrient run off from Americas factory farms… This has become more than an Aquaculture problem, it is now a total Farming Problem. As over farming has led to the introduction of chemical farming, where large factory farms are pressure pumping Ammonia into the soil in an attempt to increase production. This Ammonia pumping is killing our earthworms and other beneficial soil insects and microbes.
Hydroponics is no better… In Hydroponics plants are grown in a nutrient solution, this solution becomes out of balance when the plants that are being grown in it do not take in all the nutrients at the same rate. Once the solution becomes out of balance it is purged from the system and the solution is renewed. This purged solution has to go somewhere…. yep, you guessed it! and the problem perpetuates all over again!
Some areas of our country are now facing drought conditions! many areas of the country are facing record low conditions in their resevoirs. Here in some areas of California our Farmers are being faced with water rationing, which in turn will cause them to reduce the total number of acres being farmed and increase local food prices. As global warming progresses we will see this scenerio repeat itself over and over again as farmers and familys will be forced to reduce water usage. Orange County is implementing a plan where familys will be required to reduce overall water consumption or face serious fines! For those families who have already been exercizing a water reduction plan on their own, they will now face fines if they can not reduce their consumption further!!!
If we are to survive something has to change!
We have damaged our ecosystems to the tipping point and if we do not change the future of commercial food production will be at risk in this country! Somehow, as a collective we need to stop radically harming our farmland. We are currently injecting millions upon millions of tons of Ammonia into our soils on an annual basis due to soil depletion. This ammonia injection is to give growing plants the nutrients they need to survive, but in the mean time we are destroying the living mechanism of the soil! If you were to look at the soil a commercial factory farm in America is using to grow crops you will first find it deficient in a number of essential nutrients plants need, upon further inspection you will also find tha tit is deficient if not void in the beneficial microorganisms that live in and sustain the soil, I doubt you would find a living earthworm in such soils!
In third world countries they are looking at 2 things to change the face of food.
- Aquaponics in greenhouse production
For the purpose of this article we will be discussing Aquaponics with or without an actual greenhouse is your preference. Personally I like the shade house design for summer and greenhouse design for winter months if you live in a warmer climate… like Southern California, like I am here.
Please do some research in Permaculture, food forests, and edible landscaping… but the point of this article is Sustainable Aquaculture.
So, we have defined the two things that if combined comprise Aquaponics, but how does it work really??? And why do I call it Sustainable Aquaponics?
Aquaponics is the marriage of both Aquaculture and Hydroponics. This means that the fish are raised in water that is then recirculated through Hyrdoponic growbeds and then back into the fishtank. I say recirculated, because this is a perpetual and ongoing process. The water is constantly being cycled from the fishtank to the growbeds and then back to the fishtank again.
The fish produce waste in the form of Ammonia, this Ammonia is broken down by bacterial action from the gravel growbeds into Nitrate and then into Nitrite. This is called the Nitrification process and is compleated by 2 different sets of bacteria. The entire process of creating a nitrification bed takes aproximatly 6 weeks for the Nitrifying bacteria to become stable.
How large of a fish tank do I need to make a home aquaponics system?
How large or small of a system is up to you, but the larger the tank the more stable the system is and the fish will grow faster and remain healthier in the larger system. You need at least 250 gallons of fishtank for a truely stable system but it can be done on a smaller scale if you stay on top of things. Weekly water quality checks are a must, if the ammonia, nitrate or nitrite levels become too high you will loose fish! Check your water quality weekly or bi-weekly if you have a smaller system and do partial water changes as necessary until your system stabilizes, then do weekly checks just to be safe. The water you remove from your home system can be used to water plants in a traditional garden.
I have 3 systems that run off of 40 gallon or larger fishtanks but I do bi-weekly checks just to make sure everything remains stable. Some recomend you also check the PH and keep things in the mid range to make your plants and fish happier, do not let ph swing widely, do try to keep things stable. If your PH shifts it can cause rapid shifts in Ammonia, Nitrate or Nitrite levels and harm your fish.
How do I set up an Aquaponics system?
the first thing you need to do is find a source for your fish. I say Sustainable Aquaponics because I believe you should have a species of fish that will reproduce in your system to prevent you from having to buy your fish every couple of years or every time you harvest!
For a Sustainable system I like Tilapia they grow fast and can be table ready in as early as 5 months but I prefer them at 9 months myself as I like a larger fillet. They reproduce at an early age, as early as 4 inches with some species! The hardest part is finding your initial seed stock of Tilapia. You can try your local pet store and may find Tilapia Mossambiq or Tilapia Nilotica in some areas perhaps even blue Tilapia. But these are often smallish fish for home aquariums and not bred for the table. For these you want ot find a hatchery. Since you only need a few fish to a few hundred fish, odds are your local hatcheries won’t even return your calls or emails, and you are left feeling hopeless.
Finding your foundation stock; There are a few hatcheries out there that do sell a few Tilapia at a time but they can be difficult to find. I will tell you who I got my “seed stock” from. His name is Don and he will sell you foundation stock for your system as well as males only if you do not want to bother with raising your own. His website is http://www.tilapiahybridpair.com
I can not thank Don enough for all the help and advice he gave me while I was getting things set up. I think you will be happy with his service as well.
What do I do while I am waiting for my fingerlings to arrive?
For the purpose of this article we will be building a “flood and drain” system. This means that the system or growbeds will be continuously flooded with nutrient rich fish waste water and then drained so that oxygen gets to the roots of the plants.
Setting up the fish tank
- you need of course the fishtank. Size is up to you, use the largest you can for the amount of growbeds you need. 1 gallon of fishtank must = 1 gallon of growbed
- Airpump with tubing and airstones, use apropriate size for the number of gallons in the tank
- aquarium or pond heater for the apropriate size tank, they can range from 40 watts all the way up to 1500 watts so choose carefully, consider a second one as back up incase of failure of the first one, set the second one to a slightly lower temperature than the first one.
- water pump to circulate the water out to your growbeds, again you need to consider the number of growbeds when you calculate water pump size. you also want to make sure it can handle the lift required to raise the water up to the level of your grow beds.
- Tubing that attaches to your water pump and a sufficent amount of it to get water to all your growbeds, use proper “T’s” to connect to the growbeds if you need them.
Setting up your fishtank for an aquaponics system is a little different than you would for a home aquarium in that you do not want a gravel bottom, since you have gravel in your growbeds for the beneficial bacteria a gravel bottom will quickly become anerobic and cause your fish to become ill. You will of course want to use a dechlorinating product to remove Chlorine and Chloramines from your water before adding your fish. Make sure you put your tank someplace where you can still get in to it when your grow beds are in place above it!
Fill your tank with water, attach the heater or heaters (wait 1 hour before plugging them in), place your air stone/stones into the tank and then your water pump. Use a thermometer to insure that the heater can keep the water around 86 degrees for Tilapia a range of 76-88 is fine but they grow faster in the warmer temperatures. If you plan on Tilapia you may wish to double your air pump and stones, Warm water holds less oxygen than cold water does! Put a few feeder goldfish in the tank while you are waiting for your fingerlings to arrive, this way they can start up the nitrification process and if you loose any of these in the process it won’t be so heartbreaking.
Setting up the growbeds, your growbeds should be positioned higher than your fishtank, gravity feeds water downwards so you want the growbeds to drain into the fishtank and not your floor.
For the growbeds you will need the following
- some sort of frame or table to hold the growbeds when they are set up and filled with gravel… these WILL be heavy so plan accordingly!
- the containers for the growbeds themselves, you can make your own or use premade tubs, rubbermaids or any other tub that is large enough to do the job. Make sure you can reach the back of the tub! It should be no less than 7 inches deep to function correctly.
- 1/2 inch thin wall PVC tubing
- End caps for your PVC tubing
- threaded connector to fit your 1/2 inch tubing
- threaded elbow to fit your 1/2 inch tubing
- rubber or polyvinyl tubing to fit inside elbow, you want a very tight fit!
- 1/4 inch or smaller plastic mesh cloth to cover pvc tubing.
Assemble your frame or table that will hold the growbeds so that your growbeds will be above the level of your aquarium. You should make sure that you give yourself enough room to get into the fishtank for routine maintainence and give you access to catch any fish or fry, you may need to take these things into consideration. For my first system I only gave myself enough clearence to get my head between the growbeds and the fishtank… That was quite by accident and believe me the next set of flood and drain tubs I set up, had far more clearance than I gave this system!
For each growbed we are going to use a loop-siphon instead of an auto siphon. Auto-siphons take up too much room inside the growbed that you could be using for your vegetables. A loop-siphon works on a similar process to an auto-siphon but the siphon action occurs on the outside of the growbeds instead of the inside of the growbeds. As the growbed fills with water it will fill the siphon chamber inside the PVC tubing and then up the poly-vinyl tubing until it reaches the peek of the loop and starts to spill over, once it begins to spill over it creates a siphon effect and totally drains the growbed until air enters the siphon and breaks the suction, which in tern allows the grow beds to fill again until the siphon is again restarted and the process repeats.
To build the loop-siphon you will need to measure your growbed front to back and then subtract 3 inches. Cut a piece of 1/2 inch thin wall pvc to match your measurement and attach the end cap to one end. This will evemtually attach to an elbow on the outside of the growbed and then form your loop siphon. drill or use a craft iron and burn holes along one side of the PVC tubing you just cut in a straight line leaving about 2 inches of clearence on each end of the pipe. These holes need to be large enough to allow water and some dirt particles to pass through it but not your gravel.
Next you will drill a hole in the front end of your growbed at about center and aproximately 3 inches above the bottom of the growbed. Then you will screw your threaded connector through this hole and attach it to your threaded elbow, just before you start to tighten it you will apply a layer of silicone glue to each side of the connector to help form a water tight seal between the two pieces, then tighten the two pieces leaving the elbow at a 45 degree angle off center facing upwards. This will be where you will later attach your loop-siphon.
Once the glue has had time to compleatly dry you can then attach your PVC pipe with the holes facing downwards into your threaded connector. Then fill in under this PVC pipe with your washed all purpose or pea gravel and continue to cover the PVC pipe until you get to the level you want your growbed to be inside your container. Insert a piece of your poly-vinyl tubing into your elbow (you want this to be a VERY tight fit) and then bend the tubing so that the top of the loop is about an inch or two below the level of your gravel, and then cross the bottom of the tubing over the top of the other piece near the elbow so that it forms a loop. Look at this again and if the top of the loop is where you want it to be then, take a zip tie and zip the two pieces together. you want this tight enough so that it will not slip and readjust itself but you will be able to adjust it if you need to. place the other end of the tubing inside your fishtank. Then add water from the fishtank to the growbed until the siphon starts and make sure that the water inside the growbed only goes up to where you want it to.
Next you will take your drill or craft iron and make a hole in the growbed slightly above the level of the gravel and insert another tube into this hole (make sure it is a tight fit) The other end of this tube should go into the fishtank. This is your emergency overflow incase the primary loop-siphon becomes clogged and fails. In order to prevent your loop-siphon from clogging you will want to occasionally remove the drain tubing from the fishtank and attach another piece of tubing (that you have put away for just this purpose) and blow thru it untill it expells bubbles into the growbed, if you do not do this on a routine basis you will find it quite difficult to get started…
Anyway, you will create each growbed in your system just like the first one. Remember that it will be filled with ALLOT of gravel and WILL be heavy! You do not want your growbeds to topple to the floor or into your fishtank!
Connecting everything up; Once your growbeds are all in place with your loop-siphons correctly set and the free ends of all your tubing in the fishtank it is time to set up the pump that will keep it all running. Depending on how you have your growbeds set up and how many you have you may need more than one pump to get the job done. You do not really need a high volume pump to do the job, it is dependant on how high your growbeds are from your fishtank. For multiple growbeds on one pump you will need to use “T” connectors or a gang valve designed for this purpose. If you use “T” connectors remember to set them up like the branches of a tree and keep them even to even out the water flow among all of them, this doesn’t have to be exact, you just want water going to each of your growbeds, they will fill and drain at their own rate.
If you need extra lighting for your plants you will want to consider using fluorescent shop lights. You do not need expensive grow lights. Make sure you have one Warm White Bulb and one Cool White Bulb in each fixture when turned on, One bulb will glow a bluish color and the other one will be a pinkish color. Try to keep the bulbs a couple of inches only above your growing vegetables. Since they stay cool to the touch they will not burn your precious plants.
How many fish can I put in my system? If you have fry or fingerlings you can have one fish per gallon until they reach about 6 inches or so. Tilapia can handle crowded conditions as long as their basic needs are met and you are staying on top of water quality checks. Once your Tilapia have reached about 4-5 inches they become sexually mature and you should seperate the sexes. You can read my article on how to raise Tilapia for your table for more information on how to tell the difference between male and female Tilapia. Once you have them seperated out by sex you can then house them 1-2 inches of fish per gallon of water. Seperate out a breeding group with your best male and 5 of the largest females and keep them in another tank with growbeds as your filtratiton system. Then you can either seperate out the fishes that are carrying eggs or leave the group alone and watch for fry at the surface and scoop them up with a fine net. If you leave all the breeding fish in the tank and scoop out any babies you see, you will not have as many fry to raise up in your systems but if you are only wanting a few fish for home consumption… who cares if you have fewer fry???
How much can I expect from my system? On average you can expect at least 3-4 pounds of fruits and vegetables for every pound of fish you produce. This varies of course with how large you want your fish to grow before you eat them.
What can I do with the excess fish and vegetables that I produce in my system? This is the best part… You can can or freeze excess food you produce in your system but you can also give them away to friends, neighbors, and your local food bank so that they can distribute them to needy familys in the community! If you want to take the time, you can sell your excess at the local farmers market.
What am I going to do with the excess from my system? I like this answer the best… The proceeds from this article will also go to this project… I am planning a community services project (where I intend to apply for state and then federal 501c3 status for a project.) I will then be applying for federal and local grant money to buy the supplies needed to put 10 or more of these systems into low income family’s back yards, a portion of what is grown will go to the family who “hosts” the system, a portion of what is grown will go to local food banks and homeless shelters and a portion will be sold at the local farmers market to get money to build the next system that will in turn purpetuate the program. I am hoping that not only will the systems pay for themselves but that they will teach another way to garden that is both water wise and environmentally friendly AND help the family learn to eat more healthy along the way. I hope that eventually the family that “hosts” the system becomes as excited about this process as I am and will volunteer to help the next family and eventually EARN the system that they are hosting!
I am considering setting up these systems into a greenhouse that can be converted into a shade house during the hot summer months. I have the prototype to the system in a small greenhouse on my patio. I will be putting up how to’s on the various aquaponic systems that I am playing with for this project in later articles.
Do I believe Aquaponics is the garden or agriculture of the future??? in a word Definatly, it has it’s place in modern agriculture.
Once the systems are set up and cycled they will take care of themselves with little effort. You can grow a variety of fruits and vegetables in this system, even carrots if you have your growbeds deep enough, I like Nantes half long Carrots for aquaculture as they are a thick short carrot and don’t seem to get as bent up while growing as other varieties do. I grow Strawberries, Tomatoes, Celery, Onions, Garlic, Lettuce (by the ton!) Cucumbers, squash, Peppers both hot and bell, Broccoli, Cauliflower, radishes and many more! So far I haven’t found anything in particular that doesn’t do well in this system. The larger items like Tomatoes, Broccoli and Cauliflower must have growbeds that are deeper than 4 inches or the plants will topple unless you give them extra support.