"Michael Kenefick" wrote in message
...
John,

I think they already make such an aquarium piece. My tank has a plastic
base that is about 1/2" tall. The gravel sits on it just fine. It is two
piece that allow it to be place in and removed. The back has tubes to
help circulate the air in the water.

Mike in Ohio

Are you describing an under-gravel filter? It sure sounds like it. The
tubes in the back are not "to circulate air in the water". They're designed
to pull water up through the tube along with the rising air bubbles. this
pulls water (and junk) down through the gravel where it biodegrades. those
plates (usually) aren't durable enough to be lifted with gravel sitting on
top of them.