Quote Originally Posted by trott View Post
You might be able to line the bottom with ceramic tiles. Try thin ones, maybe drill a small hole and run the cord out of the back of the enclosure and stick the uth on the bottom of the tile. Try it with one(they're pretty cheap , couple of bucks at HD) and see what kinda temps you get. If you get good temps you can throw some aspen on top of that.
This is an idea worth trying. Another idea, if you don't mind cutting a hole, would be to cut a square in the bottom of the enclosure, say 10"x10", then get a slightly larger piece of plexiglass cut, say 11"x11" or 12"x12", and glue (or countersink and screw) it down over the top of the hole, inside the enclosure. Then, you can attach a heat mat to the bottom of the plexi like you would in a tub or plexi enclosure. The floor will be higher in the spot where the plexi is, but it won't be much, and after you add the substrate, it won't really matter.