My tank is a custom made, with no black frame on it, just glass tank. So first, it sits on a complete sheet of 1in. styrofoam.
Now that being said, all my base rock sits direct on the glass. They are large flat bottom pieces. The reef is then built up from there. I do have a mixture of crushed coral and fine sandbed in the back half of the tank, but the rock was in first. Perhaps some pieces are sitting on the sand as bit from re-construction projects.
The front half is bare bottom, {sand wise} a covered mostly in rubble. Its kept pretty clean by the Tunze pumps. I have some thick coralline growing on the bottom and many mushrooms in the rubble but no polyps.
Forgot to mention, my glass is 5/8th.
