HCA: Hermit Crab Association

Hello! I know that their substrate needs to be kept wet to have the right digging material but since i have like 7 inches deep, only the very top layer stays wet. The rest is totally dry. How do I keep it wet enough all the way through to where they can safely dig?

If you moisten all of the substrate initially it should stay damp enough. Once dry, it takes a little for it to get wet overall again

Aerated pools are the easiest way to keep all your sand moist. An air pump, line, and air-stone keeps your humidity consistently above 80% and keeps the sand moist at the same time.

okay thank both of yall so much!!!