Having no yard to grow our own vegetables living in an apartment, it was tough to accept having to buy vegetables at the market. Therefore, we committed to building a small-scale aquaponics installation around a 55-gallon tank destined for our patio. Small-scale aquaponics systems you can buy online will not satisfy our needs. They are either too small to grow a substantial amount of food or pragmatic DIY constructions lacking aesthetics. We didn’t want to add that motley collection. We wanted it to be presentable as well as durable.
Good Aesthetics Starts with Wood Selection
With these considerations, we opted to use select pine appearance boards which are smooth to the touch and are easy to work. The pine serves as both the framework around the tank and material for the grow bed. To match other outdoor furniture, we stained all the pine with blue Minwax water based wood stain and coated it with Minwax polycrylic finish. Construction of the tank framework and grow bed only took about six hours. What took lots of time was applying the stain and finish. This process lasted a week to apply several coats of stain, finish and waited for each application to dry.
Small-Scale Aquaponics System Construction
Rather than use water proof paint in the grow bed, we used 6 mil vizqueen as liner. The liner could easily be replaced when necessary without having to worry about water leaks or seepage into the wood. We drilled a hole in the middle of the grow bed to install a bell siphon, a truly amazing, yet simple technology critical for flood and drain aquaponic systems.
The bell siphon is constructed using PVC reducers combining a 3 in. x 2 in. PVC reducing coupling to a 2 in. x 3/4 in. PVC Schedule 40 reducer bushing which is connected to the 3/4 PVC Schedule 40 drainage pipe that flows back into the fish tank. The “bell” part of the siphon is cut from a piece of 4 in. x 10 ft. PVC Sch. 40 plain end pipe and a 4 in. PVC sewer and drain cap. More on bell siphons in a future post.
At the heart of the aquaponic system is a pump that lifts water from fish tank to grow bed. We chose a 400 GPH submersible pump from Amazon. All of the plumbing to connect the pump to the grow bed and used as irrigation was constructed using schedule 40 PVC 3/4 pipe.
Testing Out the Small-Scale Aquaponics System
So how does all this work? As water is pumped into the grow bed, it raises the water level to the point where it begins to trickle down the drain pipe within the bell siphon. As the trickle builds down the pipe, a vacuum is formed within the bell siphon which triggers a full powerful drain which empties the grow bed faster than the pump can fill it with water.
The siphon vacuum is broken when there is no water left to drain, air enters through the bottom of the siphon and the grow bed begins to fill again. This allows the grow bed to drain at regular intervals which is the purpose of a flood and drain system.
Lighting and Containers
Since this would be on a covered patio, we needed to install lighting over the grow bed. We used 12W LED replacements for T8 fluorescents from Home Depot since we wanted to reuse the T8 housing we already had. We also purchased 16 square plastic (5.5×5.5x6in) hydroponic pots for the grow bed from Hydrofarm. More updates soon!