Here are parts of a research paper on hermit crab care you will find useful, God luck.
4..The Importance of Clean Dechlorinated Water
The water needs to be dechlorinated. The chlorine, chloramines and heavy metals in most tap water can kill hermit crabs by causing the gills to blister (causing eventual suffocation). Aging the water will remove the chlorine, but not the chloramines, so dechlorinator is a must if you use tap water, If you don't want to dechlorinate tap water, you can use spring water instead. However, make sure nothing has been added to the water. For example, Dasani water contains magnesium sulfate "for taste", and that is bad for the crabs.However, Zoomed water conditioner is not effective and should not be used. Fresh dechlorinated water in a non metallic bowl shallow enough for the smallest crab to safely escape is ideal,some use a natural sea sponge placed in the bowl so all can can exit safely. While the "Caribbean" or "Purple Pincher" (Coenobita clypeatus) seem to do perfectly fine with only fresh water it is nice to have a bowl of salt water for them to choose from. The Purple Pincher prefers fresh water while some hermits such as the Eastern Pacific Land Hermit come from areas that have little fresh water available and drink only salt water, it is essential for Ecuadorian Hermit Crabs to have either brackish or salt water. It is best to buy a small sack of salt used for salt water aquariums as it does not contain harmful the harmful Iodine that is in table salt and a specific gravity meter to measure salinity if you are going to keep either crabs, these meters are not expensive and are usually made of heavy or plastic or ceramic.Non metalic Pet bowls heavy enough to withstand Crabs climbing without knocking it over is mandatory for all food and water. Pet bowls for crabs must be non metallic, plastic or ceramic or plastic is non-corrosive when in contact with salt water and it is best to play it safe with cermaic ot plastic bowls with fresh water too.For safety many put a natural sea sponge in the water bowl to aid in escape so they do not drown, although the Hermit Crabs started out as free swimming zoo plankton as adults they will drown if left submerged. Allow enough standing water so the hermits can fill their shells with water. Do not wash their food and water dishes with soap only but rinse it out with dechlorinated water.
6.Various Substrates
Which substrate to use is what will make the hermit crabs happy. Many hermit Crab owners use coconut fiber called Eco Fiber and can be found in most pet stores, after researching many websites and hermit keepers the coconut fiber seems to be their first choice and I have used it for aproximenly two years.Coconut Fiber comes in compressed blocks that expands when reconstituted with hot dechlorinated water, hermits love to dig and pick through it for possible bits of food and at molting time hermits will burrow into it to hide and for darkness when a molt is pending. Some Hermit keepers like a pet grade sand or harvested beach sand, both are high in calcium which adds an additional source for their exoskeletons, it is mainly meant to be used dry and that consistancy does not allow hermit crabs to bury and re-surface after molting and to just dig or burrow in. The ideal substrate is moist for burrowing making sand not a good choice in most cases. Course gravel can scratch their exoskeletons or injure soft body parts if it works its way down into their shells. Pure silica sand is not a good choice as crabs seem to do better with either the coconut or sand for hermit crab use and the pure silica sand dust is dangerous if inhaled.
Wood chips, cedar,the last two are toxic!Wood chips of pine or cedar type are not a good choice because the sap is toxic and It is hard for them to dig in this material. coconut fiber (also known as Forest Bedding®, Bed-A-Beast®, and Eco-Earth® I highly recommended by most.
13.Books
Hermit Crab Care (T.F.H. Publications)
Land Hermit Crabs (Phillip de Vosjoli
Hermit Crabs ( Sue Fox )
Hermit Crab ( Audrey Pavia )
Hermit Crabs for Dummies (Kelli A. Wilkins)
14.Materials
A varity of Books (see above)
Compressed Coconut Fiber (aka Forest Bedding®,Bed-A-Beast®,and Eco-Earth®)
Cuttlebone(for calcium replacement)
Humidity Gauge (hygrometer)
Thermometer
Specific Gravity meter ( for measuring salt content in water)
Tetra Fauna Hermit Crab Meal and Hermit Crab cakes
HBH Hermit Crab Variety Bites
Stress Coat water conditioner (helps when they are molting)
A Water Dechlorinater product for marine aquarium water
A Copper Remover for water
Marine aquarium sea salt (No Iodine)
Non Metallic water and food dishes
Tank with Mesh lid
A small quarantine tank for Molting Crabs
Extra shells in various sizes
A choya climbing stick
Pet grade natural sponge to aid in humidity when wet
glass marbles for bottom of wa