I've had a leo for about 2 years now, and after he was about 5 inches long I switched him from carpet to calcium sand. He has never had a problem with it. I've seem him eat a little bit of it when he misses a cricket or something, but he has never been impacted. The only problem I had was when I decided to go for a change and bought him blue sand. I had a BLUE leo for a couple weeks until he shed! That made me mad, so now I only get white sand, I'm gonna get the glow in the dark sand next! and get a black light for it since he's in my living room now. But this is just my opinion. I know a lot of people hate sand, but like I said I've never had a problem with it. I know calcium sand doesn't really supply calcium, but I think it's so fine that it just passes threw. But who knows.