HCA: Hermit Crab Association

Dry aragonite sand has been used successfully by some crabbers rather than using playsand. However, aragonite sand is calcium carbonate, which means it can possibly develop the same problems as calcium sand (see below) due to its porous nature and should be watched closely if used. It is larger grained than calcium sand and it will not clump or harden.

Kolorscape Playsand (Part aragonite, part silica)
Carib Sea Aragonite
Nature’s Ocean
Seachem Meridian

Hermit crab sands and reptile sands are actually a very fine calcium sand. While this may sound helpful, the sand used by itself is dangerous. This type of sand cannot be kept moist without a large risk of it developing bacterial growth, and as it starts to dry it can harden like a rock and trap or harm hermit crabs. Even when wet it clings to hermit crabs and causes them discomfort. Most of these sands have also been dyed, which can stain a hermit crab until the following molt. While this sand should never ever be used by itself, some crab keepers have reported success with using a bit mixed in with cocofiber or regular playsand.

Coral or crushed shell is too rough and too sharp to be used on its own. A small amount can however be mixed into cocofiber or sand as an easy calcium snack for both hermit crabs above ground and those that are molting.

"Live Sand" sold for marine fish tanks is aragonite sand that contains bacteria and micro orgasms, and is sold wet. Aside from being drastically overpriced for use in a hermit crab tank, the organisms in the wet sand will start to rot if not used in a cycled fishtank (in water), and therefore this type of sand should be avoided.