Thanks.... maybe if I hit dead-ends with trying to find ways to make bioactive work I will be forced to get creative, but right now I'd rather buy than make. Also, I'm really, REALLY disappointed with the ReptiBreeze cage. I've never seen one in person before but since this cham came with one I'm really appreciating the quality and sturdiness of my ReptiZoo hybrid. I am really leaning towards digging deeper into my wallet and getting another hybrid, perhaps a Zen.One way to make a 6" deep substrate tray for a 24" x 24" enclosure is from a single 24" x 48" quarter sheet of 1/4" (or 1/2") PVC.
The bottom will be something less than 24" x 24" in order to fit inside the enclosure. The remaining half can be cut into approx. 6" wide strips for the sides. Some shortening of the sides will also be required so they don't overshoot the bottom.
PVC glues very easily with PVC cement. Read all directions & precautions, and work only in a well-ventilated area away from pets—this stuff is really stinky and the fumes are bad. It works by melting/welding the PVC pieces together, so work carefully and quickly—no do-overs!
Lots of 'How-to' articles & videos on working with the stuff.