I know it's the age old Uro question. I was just curious what everyone else was using for substrate. After hours of debate I decided to go with washed play sand. (Switched from Repti-sand).
Originally we were set-up with washed play sand. But due to injuries we changed to carpet. Our Mali had a large burn and blistered on her sides from a habba hut. Our saharan had a broken back and was paralized. We may go back to playsand in a year when they are both completly healed.
A good old fashioned fine covering of play ground sand (make sure it is steralized, and not made for sand blasting). But gernally in all my years being around uros I have never seen any inpactation with it or nothing. Plus they love to dig...give them enough to dig and I always say let the reptile mimic its natural behaviour and it will do a whole lot better.
Has anyone tried this stuff? http://www.exo-terra.com/EN/products/desert_sand_red_i.html Looks interesting. No petstores around here cary it. If it is the same consistancy as playsand might work.