You can place the substrate on the bottom; I will suggest some for you in below:
- Ceramic tiles: It is the new trend for the substrate. The tile is easy to clean but still giving the appealing set for the tank.
- Newspaper: one of the best saver substrates, which is easy to maintain, its look is not very attractive, though. If your pet love to dig without worry about impaction, you should choose this type. However, the newspaper will retain humidity.
- Carpet: The synthetic carpet will be the best choice for simulating grass or deserts.
- Sand: Sand is the most natural material. Using the clean and free foreign debris sand for your pet, don't use sand for babies or juvenile beardie.