I tried both aspen and cocofiber for my hoggie, and I felt more comfortable using the cocofiber so I'll be sticking with that. All of what Deborah said, and a hot spot of 90 and you should be good. My guy "swims" through his substrate quite a bit, they're definitely more diggers. I also think a bioactive would not be great for these guys. Mine is in a tub, but he basically has a hide and a water dish and he's eating very well.