The high tunnel aquaponics system below has a 1,700 gallon fish tank and a 165 square foot grow bed. The entire floor area is one big 15' x 11' grow bed filled about 10" deep with river gravel. Water from the fish tank carries fish waste through a set of channels in the grow bed, where it is consumed by composting worms, broken down by bacteria, and absorbed by the plants. The resulting clean water is then pumped back into the fish tank in a constantly repeating cycle. The circulating water also creates a 'heated floor' effect, which is an important benefit in winter. The results have been incredible, and I never need to bother with watering, fertilizing, weeding, or spraying with pesticides.
I've had up to 800 fish (1,200 pounds) in the main fish tank for extended periods for overwintering, but that much ensuing fish waste can overwhelm and clog up the grow bed in a hurry, so it's important to pre-filter the poopy water between the fish tank and the grow bed if you're going to push it that hard.
