Pet hermit crabs, no matter how many they are in one enclosure or tank do not need regular weekly clean ups. Once or twice a month should be okay, depending on how much grime the actual enclosure gets. Assuredly though, there won’t be much grime to begin with if you are only consistent in removing uneaten foods from the day before, and in changing their drinking water (and washing their water dish while you are at it) about twice a day. It should be stressed here that these pets benefit a lot from as little human handling as possible.
However, in case your pet’s enclosure or tank would need a good clean through, the question is “How to clean a hermit crabs aquarium?” The first thing you have to do is to choose a temporary location for your pets while you are cleaning the tank. Another water tank wherein your pets most likely won’t escape is always a good option. Shoe boxes, kitty litters and other shallow pans do not make great temporary locales since your pets would most likely escape from these in a hurry. Further information on how to care for a hermit crab you’ll get at http://www.healthyhermitcrabs.com.
Next, you simply take a fish or kitchen strainer, (preferable the ones with tiny sieve holes,) scoop some of the sand or coconut fiber substrates and let it run under the tap. These should rid of most crab poop, uneaten meals and other whatnots. Place in another temporary holder and let it dry out somewhat. If there are larger bits and pieces you want to rid off, simply pick through the substrates with your fingers. Do this until you have sieved through all the sand or coconut fibers.
When cleaning the tank of a hermit crab it is also recommended to replace the substrates with the recommended consistency: sand should be moist but not dripping wet and coconut fibers should be shredded and not impacted. Replace the food dish, water dish and the hermit crab toys (if any.) And you are done.