Ive seen it on here before. Is there a certain type of tile that is ok for use in ray tank or are tiles in general ok? Im asking because i removed my sand and the glass bottom is causeing my arrowanna to get drop eye. I wanna resolve this before its too far gone. If anyone has experience with tiled bottom please chime in. Do you absolutely need to grout it or can i just place the tile on the bottom of the tank and not have them come up with the rays circulating the tank? Thanks