One Barrel Aquaponics System Construction
This post gives instructions on how to build an Aquaponics system from one 35 or 55 gallon Polystyrene barrel. It may not be detailed enough for everyone, but should be enough info for the Do-It-Yourself -er. You might want to see the overview article here.
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Completed system, February 10, 2013.
These instructions are for the 55 gallon drum but will work with a 35 gallon drum as well. The main differences are:
- 35 gallon – Cut to split the barrel and make the growbed is 8″ from bottom of the barrel
- 35 gallon – Oval hole is 5″ down, 5″ tall, and 8″ wide
- 35 gallon – Plastic hose is 30″ long or as you prefer
- 55 gallon – Cut to split the barrel and make the growbed is 8″ from bottom of the barrel
- 55 gallon – Oval hole is 6″ down, 6″ tall, and 9″ wide
- 55 gallon – Plastic hose is 40″ long or as you prefer
They both use the same plumbing parts and pump.
Buy a 55 gallon barrel that has a sealed / solid top and has only been used to store food in it. This is called a food grade container. Use a dark color barrel so the sunlight won’t get through to the water and grow Algae. Make sure the barrel is more conical (tapered) than tubular (straight sided) as the design depends on it.
There are usually two plugs on the top of the barrel. Remove one of them and wash out the barrel.
Make sure the plug has a gasket on it (comes with the barrel) and screw it in tightly.
Mark and cut off 8 inches from the (now) top of the barrel.
Sand the edges of the barrel where you cut it so it will be smooth and attractive looking.
It should have smooth edges and look like this.
Six inches or more, down from the cut, draw an oval
Then cut an it out for access to the fish tank that will be made out of the “bottom” of the barrel. I used a 4″ hole saw (cup type) to cut out the left and right sections of the oval. Then I used a fine tooth blade on a reciprocating stab saw. Next I use 120 grit sand paper on a piece of wood to shape the hole.
Place the 8″ piece you cut off, into the open end of the (new) bottom (Oval cut not shown here). This 8″ piece will be our grow bed.
When you have the grow bed inserted so that it is just a little snug, drill four (4) each 1/4″ diameter holes near the top of the larger piece of the barrel and through both barrel pieces. These bolts will hold the grow bed in place on top of the fish tank. The holes I drilled were at 12, 3, 6, and 9 o’clock position. You can use more bolts if you like.
Insert nylon or stainless steel bolts, nuts, washers and lock washers. Regular metal will affect the balance of the biology in the system and/ or rust.
Inside view of 1/4″ nylon bolt.
Next you should install an overflow drain and a water inlet that will be connected to the pump we will locate in the fish tank. I used 3/4″ for the drain and 1/2″ for the water inlet.
Locate a 3/4″ PVC pipe that you can use for a bulk head connector, to use for the drain. A bulk head connectors is what a connector is called that passes through a wall or tank. I found
I have used PVC pipe intended for water or electrical conduit usage. The one with the longest threads and the squarest shoulder works the best.
Also, note that you may optionally uses a neoprene flat washer or two. Sometimes an O-ring works.
Here is a shot of the system with the grow bed mounted and the holes drilled for the drain (tallest) and the water inlet.
This is what my 3/4″ drain and 1/2″ water inlet look like up close.
Make sure and drill a few holes in the drain / overflow pipe (on the left in the picture). This makes sure that all the water will drain out of the growbed when the pump is turned off. Also, should you pump too much water into the growbed, the same pipe acts as an overflow pipe.
Note the small holes at the base of the bulkhead fitting on the drain, and the mark at the top making it easier for me to align these holes and the ones in the pipe, when I re-insert it.
You will want the water level flooded to a specific height in the growbed. After I took this picture I drilled two larger holes (not shown) in the drain / overflow pipe to set the level I wanted for the maximum water in the growbed. I choose for the water to be 1″ to 1 & 1/2″ below the top of the clay beads at it’s highest level. The holes need to be large enough that they drain the water faster than the pump can deliver the water, else your plants will flood and your clay beads will try to float.
I have installed a 2″ PVC pipe to act as a strainer so that the media (beads) don’t get into the drain / overflow pipe when I need to remove it for cleaning or inspection. Also, I have pressed an elbow (Ell) on the water inlet so the water can be directed into the growbed and not into the air 🙂
Note that I did not glue any of the pipes. I like to be able to pull them apart for cleaning.
Below the Scene
Here is what the bottom of the growbed and plumbing look like. The water from the drain / overflow is directed to drop into the fish tank water so as to provide oxygen to the fish. This may not be enough oxygen for the fish in very hot weather.
The water inlet 1/2″ pipe is connected to a clear hose that is a press fit. It also is press fit onto the pump on the other end.
The drain pipe could be just a straight drop from the “bulkhead” piece that goes through the growbed bottom. This would save you a couple dollars and still give you a good splash that creates air in the fish tank water for the fishies.
Or you can just let the drain go straight down. Be sure to put a piece of pipe on it so that it does not splash out the rear hole.
The pump provides water flow and the water splashing into the fish tank water provides the oxygenation for the fish.
The pump is the sold by Harbor Freight and is the 158 GPM model. Make sure you get a pump that can pump water high enough / hard enough to get to the grow bed, when it has been used for a while and is less clean. Here is the info: 158 GPH Miniature Submersible Fountain Pump – item #68396
Notice the Maximum head lift is 3.6 feet. That is how high the pump can lift the water clean. As it gets older and dirtier that gets lower. Keep your pump clean.
You can see the Pump, and tubing that goes to the 1/2″ PVC water inlet in the growbed, in the bottom of the fish tank. Note that the bottom of the fish tank used to be the top of the barrel, when it was one piece. The drain plug can be seen in the picture, and is screwed in snugly so it will not leak.
The pump comes with 2 plastic adapters that press fit into the outlet side of the pump. Use the one that the ½” tubing fits onto snugly. The pump comes with the small fitting installed, just pull it out.
Connect the tubing to the water inlet in the growbed, by pressing the end of the ½” clear tubing into the end of a short piece of ½” PVC pipe, ex: 3” long. Then press fit that pipe into the bottom of the water inlet PVC pipe. This way allows you to remove connections for cleaning, etc.
By having the pump connected with longer flexible hose, you can pull it out of the fish tank oval hole and get to it easily. Tye wrap the pump power cord to the hose on the pump, but not too tight!. This will allow you to lift it out by the power cord and not pull the hose off of the pump.
I drilled a hole in the rear of the fish tank barrel, just below the growbed, to use as an exit for the power cord.
Flood Control, the Timer
My system is set up with a timer rather than the often used Bell Siphon. My timer is set to run 0:15 minutes at the top of each hour. When summer days get here, I may need to make it run more often, to help keep the plants cool and the fish oxygenated.
This is the $10 mechanical timer I purchased from Harbor Freight for around $10.
It just plugs into a wall socket and you plug your pump into the side. The red slide switch allows you to manually turn the pump on or to turn it to be operated by the timer.
You just press the index tabs down so that it will turn the timer on for that 0:15 minute period of the hour.
I plugged the timer into a power strip and hung it on my house under the roof overhang and high enough so that it does not get wet. The timer is not water proof so be careful. I use a GFCI outlet but you would be better served to use a GFCI outlet inside the house and run the power cord outside. Better yet use a waterproof connector box to house the timer and a GFCI outlet.
Use at your own risk. Consult a knowledgeable professional!
For the media I used Plant !t which is an expanded clay bead, like Hydroton. It is light, reusable, and has lots of open space inside for the bacteria to reside and thrive. You can use washed 1/2″ – 3/4″ diameter river rock, which contains no limestone or marble as this changes the pH of the water. You want the pH of your water to stay around 6.8. This is a happy compromise for the fish, the plants, and the bacteria which are the three key biological elements of the Aquaponics system.
Your system will look something like this. This is the 55 gallon barrel Aquaponics system
This is the 35 gallon barrel Aquaponics system. It is about 3/4th the size of the 55 gallon system. It is a lot easier to move (scoot) around when full of water, but has less grow bed space too.
Water Volume Control
If your pump happens to be over powerful, you can rotate the screen on the end of the pump where it takes in water, to lower the water pressure delivered. You don’t want to blow your plants out of the media!
If you buy a pump that does not have this, you can drill a small hole in the hose near the pump or make a pressure relief valve. Here is a simple one I made for another project. It is just a piece of 3/4″ PVC pipe slit down one side and slid over a piece of 1/2″ PVC pipe, both drilled with a small hole, and installed in line with my pump. I just rotate the 3/4″ pipe to expose the hole in the 1/2″ piece to let water pressure out.
Rear view showing the slit. I use the marks to keep the holes in both pipes alligned.
Now plant some seedlings or transplant some small plants. We put the system by our back door to keep the plants close to the kitchen for cooking. We planted Cilantro, Basel, Lavender, Thyme, Lettuce, and Strawberries.
Plus One Month
March 11, 2013.
One month later, with no added heat, no special treatment, and with lots of cold mornings, the system still grows plants. The Strawberries are not growing much but the other plants seem to defy the season and have grown some. I am anxious to see what the small, simple, Aquaponics, balanced Eco-System, can do when the weather is “in Season”!
“Lavender does not like wet roots” at least that is true in dirt gardening. I find a lot of the “rules” are applied differently in Aquaponics. As you can see my Lavender has lived and grown with “wet roots” for a month already!
Note: The barrel has gone out of round since I built the system. As you can see the barrel seems to have “squared” itself off around the planes of the four bolts. My approach to construction seems to have all the weight of the growbed supported largely by the four bolts, with little help from the not-tight-fit into the bottom barrel. I suspect that the design would have worked better if I had pressed the growbed piece of the barrel more tightly into the larger piece of the barrel, and used 8 rather than four bolts.
I have been asked which fish to use. I recommend gold fish as they are easy to buy and cheap, like from PetCo store for $0.15 each as feeder fish, are hearty, easy to care for, and live through the winter.
Best wishes with your one barrel Aquaponics System!
Here is the link to the parts list for the One IBC Aquaponics System Construction.
You need to attend one of my classes that teaches it to get the password.
Leave a message and or contact me if you have questions.
P.S. Barrels are good for other projects too! This is the dog house I made for my dogs.