I put a snail in there to keep away any algae plus clean up uneaten food and the snail poop is bugging me. I can suction it out a few times a day but replacing the water isn't so easy-I can't estimate water conditioner for a pint of water and I can't use water that's been sitting because it'll be too cold (no heater). I feel like if there's gravel at least I don't have to look at it. lol. Is it a bad idea? I figure they'll be in there for a month or more before I can move them back into the big tank, right?