I only use ceramic tile. I just line the bottom of my tank with paper towel and place the tiles on the paper towel. No grout or anything. Most of the time you can get a nice tight fit, with a little trimming of the tile. As far as cleaning, you just put up the tiles, clean them, let them dry and put 'em back in. There's no risk of impaction, they help keep their nails in good shape.