HCA: Hermit Crab Association

I was considering changing the substrate of my tank from eco earth to all sand. I just wanted to know if it could possibly hurt the crabs to do that. Besides the fact that I've had this substrate for over a year and the tank is starting to smell. I'm not sure if its the food or if one of the crabs has died.

All play sand is safe and appropriate.

I've been using straight sand for over a decade now and prefer it. I do the initial mix with saltwater as it helps with controlling odors and any stray mold from food or organic decorations.