The Importance of Water
Land hermit crabs require both fresh and saline water ponds or pools to drink from. It is recommended that you add a water conditioner such as Seachem Prime which will remove chlorine, chloramines and heavy metals as well as ammonia from their fresh water.
You will also need to make up a marine-grade saltwater pond. Instant Ocean sea salt is popular.
Hermit crabs will drink from both and regulate the salinity of their shell water, which keeps their gills moist and helps to keep them alive.
Land Hermit Crabs can drown if submerged in water for an extended time (fishermen say around an hour), but they have been observed bathing themselves in shallow pools to replace shell water and wash out any foods and wastes from their shells when in the wild.
Hermit Crabs urinate through their antennae, so any water spills during handling are shell water. Hermit Crabs have an anus located on the end of their abdomen and have been observed to flick any wastes (droppings) out of their shells. These faeces are often brown coloured and look like small sausage or ball shapes which consist mainly of sand and undigested foodstuffs.