How to Set Up an Isolation Tank
A small plastic or glass tank can be used for the isolation tank since molting crabs are inactive and do not need a lot of space, although there should be enough space for food and water dishes. A deep layer of sand (or Eco Bedding) should be used - other substrates do not provide the right conditions for digging. Provide both dechlorinated water and salt water, as well as food in the isolation tank. Make sure some calcium-rich food is available such as cuttlebone, Calci-Sand, or boiled egg shells). Also provide a hiding spot if possible as well as a few larger shells for the newly molted crab (who may or may not change shells after molting).
The most impoirtant thing to remember if you use an isolation tank is to make sure the temperature and humidity are right. This means you will need to invest in a humidity gauge for the isolation tank and most likely a small heating pad as well. If the conditions are not optimal in the isolation tank, you will be better off leaving your molting hermit crab in the main tank. Temperatures a the high end are recommended for molting crabs - CrabbyTalk.com recommends humidity at 78-80% and temperature around 78-80 F. The proper humidity is extrememly important as mositure is critical to the molting process.
A modified version of the isolation tank involves using a smaller tank (e.g. a plastic tank) inside the main tank. This makes providing the same heat and humidity as the main tank easier. You will need to place a deep layer of sand in the bottom of this tank and provide food, water, and shells as for the isolation tank.
Some owners elect not to use an isolation tank: see "Is an Isolation Tank Necessary for Molting Hermit Crabs" for further discussion.
Go To Hermit Crab Molting FAQ for more on molting hermit crabs