I am working on a 10 gallon leopard gecko habitat and using the polystyrene foam/grout method (first time). I do not intend to use any sort of particle substrate, but rather I want the floor itself to be "rock." The plan is to "glue" the foam rock formations that I have carved to the glass bottom, and then coat the ENTIRE thing (foam and glass bottom) in layers of grout. But before I continue, I have questions! 1. Will the grout even hold to the glass? Or will it flake off over time? (keep in mind that after the layers of grout, I intend to do a nice acrylic paint job and then finish it off with some form of sealer). 2. Will the under tank heater cause any problems with the grout or foam? Or paint? Or, for that matter, the gecko? Are UTHs safe without a layer of substrate? If needs be, I can of course simply add a base layer of foam over the entire floor. That would give a cool opportunity to carve details on the floor, but I am not so sure I want to raise the whole thing up another layer. Has anyone had experience with this? Are there any obvious "red flags" in my plan? This is my first build so I could use ANY advice on the matter!