When I went to get play sand at Home Depot, there was another type of sand that looked nicer, the white type... but it said right on the bag that it couldn't be used in aquariums. Play sand was a royal pain to rinse out, I didn't get all the dust out and it turned the tank brown (100% water change fixed that). But, even weeks later, it was coating everything with a fine layer of dust and kept getting into the filter and making grinding noises (which can't be good for the filter), so we swapped it to pool filter sand. Pool filter sand has bigger particles than the play sand, it doesn't have all the dust and tiny particles that never seem to stay settled. They look much the same, and I've had no problem with the pool filter sand. I think you need to go to a pool place for it though, not a Home Depot. I know other people have play sand, but that's just my experience with it.