As always I was thinking about aquaponics and I thought of an idea of a chift pist type system. ( or at least I think) How it works is a; gravel sump tank comes out of a overflow and goes through the entire grow bed with another overflow, then a raft system gains water from  the overflow from the sump/gravel bed and uses a water pump to go back to the fish tank through N.F.T. . If this is crazy I…