I was told taht the glass tanks are supported from the perimeter glass, not the bottom glass, and byplacing insulation under it, that would transfer the weight to the bottom glass, which was not designed to carry the weight of the tank and water.
So support only the edges.
It kind of makes sense but then again it doesnt. The perimeter glass supports the bottom glass through the silicone, so whether the silicone supports the wieght of the tank from teh bottom glass then transfers it to the perimertor or visa versa, does not make sense...
I am not an engineer so I can not give an answer, onlhy relay what I was told.
Bill