I am not leaching out all of the worm casting nutrients, just enough to suppliment the aquaponics system. The goal is, and I will do this shortly, is to create a system where folks with a minimum investment can supplimently feed a family. Worms little or no cost, seeds a minimal cost, aquatic animals, if they can snag them out of a waterway great, but fingerlings of native fish are available at free or low cost. Very little cost to supplinent for iron or whatever. I am certainly doing overkill with my setup it's test beds.