I agree with Frank79. However, I do have some sand in Vinny's tank. I have tiles over 3/4 of the floor and a section of sand for her to dig and play in...but I have extra tiles that I slide over top of the sand area when I don't want her to have access to it. Sort of like a removable sand box. So, if she's been fed and I'm waiting for a poop, then I slide the tile over the sand so I don't have to worry about her pooping in it (although she usually prefers the bathtub!)
As with almost everything in life, there is always going to be arguments when it comes to particle substrates and safe alternatives, just do your research and find something you are comfortable with.