I have always just used coco coir for my fossorial species and never had a problem with it, until I did. recently I had burrow collapses in 3 tanks, they were all set up about a year ago and left undisturbed and there were no changes in the environment that I can think of that may have caused it. anybody here who keeps a lot of fossorials, what do you use for substrate? ive got a lot of T's so buying some eco-earth or bio-dudes stuff really isn't cost effective, though if that is what I need to do.......