on another note- as far as a digging box. I have tried several types. with my terrestrial gecko species i have used small low profile tupperwares with top or side entrances filled with topsoil, coconut fiber, spagnum moss or sand mixs. the geckos seemed to prefer this so much over their tiled enclosures i just switched the whole enclosure over to the substrate. my desert iguana is kept on a very course, gravel-like sandstone tile with an open topped tub filled with around 4-6" of fine sand for him to dig in, its his sandbox. works great for him as he is a very messy eater that would get sand all over his fruit and veggies if fed over it or near it. i have even wetted down his sandbox and let it dry hard then placed it back in the tank for him to dig burrows in while it was hard enough to keep solid shapes. as he digs it goes back to loose sand and then i just pull it out wet it and let it harden up again. his tank is far too hot and dry for any bioactive vivaria so i dont even attempt it.