There’s definitely a lot going on with the aquaponics system, but it’s a lot of trial & error. Farmer John is still trying to figure out what works best. Meanwhile, the tilapia are growing rather quickly.
MAIN FISH TANK
What we’re looking at here is the access hole cut in the IBC container used as our main fish tank.
The floating contraption with greenery is styrofoam & screen door netting combined to hold duck weed and protect it a bit from the hungry tilapia.
The white coil is used as a heat exchanger for our propane water heater.
June 2015 update: We don’t use this heating method anymore.
TILAPIA IN THE SUMP TANK
We intended for the tilapia to stay in the main fish tank. However, they are so tiny many of them swam right through the pipes and into the sump tank. It doesn’t seem to be a problem, so we are leaving them there.
GATHERING & CLEANING ROCK
The main growing medium we chose for our grow beds is expanded clay pebbles. They are expensive, though. So, we are filling half of each of the grow beds with gravel, then pouring the clay pebbles on top. We wanted to use the gravel we had. And, what we had was 3/4 minus. But to ensure the grow beds drain well, Farmer John wanted only the 1/2″ or larger rock. So, he screened the 3/4 minus for those larger pieces.
Farmer John used hardware cloth & an extension ladder to screen the gravel. He started at the top, pushing the smaller pieces through the hardware cloth and into the red tub. By the time he got to the bottom of the hardware cloth all that was left on top were the larger pieces. He dumped the small gravel out of the bin and replaced it with the larger rock, then rinsed it.
Bottom Right Photo: The gravel anchored the bell siphon housing. Farmer John made the housing out of 6″ pvc pipe and cut slots for the water to flow through with a table saw.
June 2015 update: Farmer John is concerned that this gravel has been making the aquaponics water too acidic.
MIDDLE GROW BED
The bottom half of the grow bed is gravel, the top half is expanded clay. A tomatillo seems happy with this combination.
RIGHT GROW BED
The Chinese cabbage & arugula we planted a couple months ago don’t seem to enjoy the warm water of the aquaponics system and warm temperature of the greenhouse.