[Borderjumper]

I've googled all morning, and what I am finding is.. Never put foam under a rimmed tank. A rimmed tank is designed so that the weight of the tank sits on the rim, which displaces the weight up the sides vertically. makes sense, as glass it strong vertically and weak horizontally. IF you put a rimmed tank on styrofoam, the weight bearing edge will compress into the foam until the glass is being pushed down onto the foam, your now messing with the design intent and instead of all the force of the weight being transferred vertically up the sides, it's also pressing up on the glass bottom which eventually cause it to flex, and as I know only too well, horizontal glass doesn't flex well when the corners are being pinned down by over a 1000lbs of water and rock.