2 Pack Hermit Crab Water Tank, Cage Accessories With Climbing Ramp, Aquarium Salt Water Pool for Small or Medium Habitat Home Transparent

These are the pools I have. https://a.co/d/0a01OViq They're about 2.5in x 3.5 in. I did a little more research and I am feeling better about as long as there is a way for the crabs to get out, not worrying so much about the pools. I thought they would drown pretty quickly, more like humans. I'm looking at these though, so there's a more gradual entrance to the water for the littles and plenty of space for the bigs. I'll def get more moss and thanks for the sand suggestion!