Not the walnut shell it's toxic to dragons--- - carpet is expensive- you can go w/ slated ceramic tile and cut to tank size- no real coarse but no smooth either-- easy to clean w/ vinegar and water 50 50 solution- also I would not grout use an thick shop paper towels underneath- or NON adhesive shelf liner--from your local home improvement store cut to tank size and clean w/ vinegar and water 50 50 solutionIm getting my bearded dragon setup in his bigger enclosure and im not sure what substrait to use. I was thinking about getting the Walnut shell substrait or carpet idk. What substrait is best?