Maximum Yield USA April 2018 | Page 53

A quaponic systems rely on the nitrification cycle to supply nitrogen to plants, but if too much is available, then denitrification can be used to lower those nitrogen levels. The systems range from the simple to the elaborate. At the simplest, water can be scooped out of a small aquarium and used to water a small houseplant. Some of the most complicated are large commercial aquaponic systems that harvest both edible fish and edible vegetables. In my backyard, I’ve had a simple aquaponic system running for more than a decade with minimal fuss. The pump has been replaced twice, and the fish are (or are the descendants of) the original fish. A Simple Backyard Aquaponic System Water from a small fish pond is pumped to a series of half wine barrels that start at the top of a small rise and end at ground level. The elevation of each barrel is key since they gravity feed one into the other. Each half barrel contains lava rock and a pipe near the rim leading down to the bottom of the next half barrel, which is set lower than the first. The lava rock provides mechanical filtering as anchorage for the plants and a hospitable environment for beneficial microbial growth. A third and fourth half barrel are situated lower and lower yet, and the bottom barrel empties back into the pond. With this arrangement, water travels from the pond via pump to the bottom of the first half barrel, through the lava rock to the top, and then through the pipe to the bottom of the second barrel. It then repeats this process through the remaining barrels until returning to the pond. “The lava rock provides mechanical filtering as anchorage for the plants and a hospitable environment for beneficial microbial growth.” grow cycle 53