(This is not our set up, this is a much larger commercial setup)
My brother and I came across this ingenious way to grow both protein and vegetables efficiently and organically and sustainably. I believe my brother turned me onto the process. We did our research and due diligence and decided it made too much sense not to try it.
We live in a cooler climate , lower central British Columbia Canada, so we knew we would need a greenhouse to keep the fish warmer in the winter months and to also allow us much longer growing season. I had load of older 1"x10" siding from a housing remodel and my brother had a metal frame from one of those portable shelter structures. Seemed like a good mix. We decided to build the new aquaponics venture on his property as he had some acreage and I had a big city lot.
First the recycled structure went up. It was a bit of a process as we wanted to make it as weed free as possible. So we build a plank floor that would be able to support the weight of the fish tanks as well as the grow beds. We wanted a greater growing height than just the metal frame would allow so we constructed a 3 foot high knee wall around the the out perimeter. And on top of that went the metal frame. We then wrapped the metal frame with cedar and then built panels with double layer UV rated poly to fill in between the frames. This allowed us to just remove a given panel and repair it if the need should arise. We did a ridge vent and a ground vent with a fan to pull in cool air when needed.
The next step was to size out our grow beds and our fish tank. These calculations are important as you want enough grow bed and enough water to ebb and flow these beds without shocking your fish with low water levels. I won't go into all the specking of this but will say the we had a main fish holding/return tank, a swirl tank for solid waste collection and a reservoir tank for grow bed flooding. Above our fish tank we had what I call a wet bed or raft bed. It is a grow bed that continuously cycles water from the fish tank allowing the plants roots to pull nutrients out of the water and then the water fell back into the fish tank directly to allow for aeration/oxygenation of the water for the fish. Our ebb and flow beds were feed from the reservoir tank. The reservoir water was skimmed from the top of the swirl tank. this set up was done to keep the organic fish waste out of cleaned rock grow beds.
We utilized a dual pump system. A smaller pump that continuously supplied water to the wet/raft bed and a second more powerful pump that emptied the reservoir tank into the ebb and flow beds in a timely matter.
The ebb and flow beds you grew stuff you didn't want constantly wet, things like root veggies, the idea here was to fill the beds with water in about 10-15 minutes and then have the drain system empty the beds back into the main fish tank(more aeration/oxygenation). These beds worked on a 3 hour cycle.
Because of our northern climate we were limited in the type of stuff we could grow. We did not want to go in for grow lighting in the late fall, winter, early spring. We were also limited in the type of fish we could use because of the conflict between ideal water temperature for local fish and the desired water temps for the plants. We ended up going with goldfish as they could handle the warmer water for the plants in the growing season and the cooler water temps when we were not growing.
The process worked rather well and plenty of delicious nutrition fruits and vegetables were grown, everything from beets to berries. We obviously did not gain the benefit of a food fish because of our circumstances however we did prove the concept.
In a more temporal climate tilapia or a "natural to the area" fish could be used and then you could harvest both veggies and vittles.
Oh and just a foot note here the system is a FORCED organic self sustaining system as you can not use any fertilizers or herbicides or pesticides or you will kill your fish. Your fish waste is the food for your plants so dead fish equals dead plants. The system is scalable from a small household fish tank with pet fish all the way up to commercial viability.
Just one mans experience and opinion. Take what you like.