My 300 gallon Drop Off Reef Tank Build

[Gripenfelter]

The top piece will not be siliconed in. It will be sitting on top with a hole in the middle. Air won't be trapped. Two glass pieces make up the top of the shelf and are removable in case I ever need to get in there.

Also the braces are sitting on top of those two side pieces on the bottom so there is about 3/8" clearance for sand and water to flow through under the bottom. Same goes for the top piece. There will be a slight gap. I have lots of tiny snails that bury themselves in the sand so they will help keep things clean as well.