would a 55 gallon drum set so that the bottom of the drum is about 1ft lower than the water line of a 180-200 gallon tank that's about 24" deep create enough head pressure to run ugj system on gravity alone? My thought is to have the overflows run directly under the tank to a sump. From there it would be pumped into a crawlspace where the filtration system would be. Then gravity feed back into the tank. The tank itself would be a diy plywood with the front pane from a 6foot 150. ( the 150 is already disassembled it was free because of a cracked bottom.)