I have about 12 inches of clearance under my aluminum tank, a highly unusual
configuration. On my list of big projects is to cut into the flat bottom
and attach a big sump for water and other crud to sink into. It's a nutty
design with a big flat bottom so there is no sump point but it probably
keeps any stuff in the bottom of the tank swirling around in suspension so
it goes through the filters bit by bit. The suction is in the center so
unlikely to pick up much. Maybe it isn't such a bad design after all.

--
Roger Long