Has anyone ever used florist foam then covered it with silicone?
Are you talking about Oasis foam, or green styrofoam? Oasis crumbles very easily when wet, and probably wouldn't last long in a typical viv. The green styrofoam would work, it's porous surface would probably hold on to the silicone pretty well, and it's fairly rigid.
the green styrofoam, Our local walmart has it fairly cheap and I'm going to attempt to make a waterfall out of it for my son's firebellytoads. Thanks for the help