i recommend filtered water. The water coming out from Diamond water filter or NESH filter is suitable.

Be sure to prepare a seperate water bowl for them. 1 bowl for freshwater which is the filtered water, and one bowl for saltwater.  I recommend Red Sea brand sea salt.

tap water will be fine as long as you add anti chlorine into it. And you dont have to buy salt water. You just buy the sea salt. Pets Safari got sell Red Sea Salt.

Is your tank have enough substrate? What is your tank's humidity and temperature.

Dont always feed them commercial food. Add some fresh food into their diet.

The crabs may be destressing right now. Given the correct temp and humidity, they will be fine. And normally they are active during the night .

Boiled tap water can be used for hermit crabs.

@ahtiven : 5 inches of substrate and make sure you get a termometer for the tank. If possible, get a humidity reader as well. New carbs are rarely active when they first brought into homes as they have to adapt the enviroment. This is known as Post Purchase Stress ( PPS ) .. they need intensive care and to make sure that your crabs is comfortable in your home, spend more time with them, play with them. Talk to them gentally as they DO understand emotion and feelings

Also, you have to monitor the crabs really frequent. When crabs get too stressed, they would just crawl out from the shell and run around shell-less.

Next thing to make sure is you get extra shells just incase they are in need of changing shells. Each crab must have at least 3 shells minimum. For instance, you bought 3 crabs from a pet shop and you have to get 9 shells in total that is the size of the current wearing shell or slightly bigger from the current.

Try looking for this product : Exo Terra artifical Vein, Exo Terra feeding / water dish. The price is varied from RM8.90 till RM49.90 for the dishes while RM15.90 for the Artificial Vein ( Medium ) while RM29.90 for Coarse Artifical Vein. Some plastic products contain uncertain amount of toxic so try avoid any of it. Large driftwood is good as a decoration item. Just make sure that you soak it in warm water before you use it.

Oh i forgot this : Crabs do need privacy. If they want a moment of their own, Exo Terra Reptile Cave is a good choice for them. Varied in size ranging from RM 8.90 till RM48.90 (Small to Extra Large) or you can get those small flower pots (may it be plastic or clay) to make a hideout place for them. Oh, if you feed bread to them dont be surprise to see balanced bread being stacked in the hideout. 

For the substrate, get some fine sand that is non color-ed. Geo-System substrate is the brand of sand i am using for my crabs. Make it 4 ~ 5 inches depends on the size of your crab. Also get some smooth river pebbles for extra flavor. The price for that is RM 8 per 4kg? . There another sand brand that is optimized for reptiles and crabs, Repti-sand is the name. Though its expensive ( RM16.90 ~ RM29.90 ) but the sand is extra fine and well processed.

Optional substrate to enhance the tank environment is the Exo Terra Jungle Bedding. It comes in a fixed size pack or i would say, rather huge pack and tagged with a price of RM19.90. It consist of wood bits that is excellent in humidity management so you wont have to spray fresh water on the substrate that frequent.

Sorry if i typed that long English is abit choppy due to me eating dumplings while typing.

For fresh food, of course you have to take it out after 24 hours or it will start to smell, especially in a humid condition.  And yes, the substrate is a MUST. How small your plastic container is?

these two are land hermit crabs.

the one on the right is Ecuadorian  hermit crab and the one on the right is purple claw hermit crab. they are 2 different species. however they share many similarities like habitat, diet and physical appearance. the purple claw is identical to the light purple colored larger claw.

hi there...new here...
just bought my hermit crab today...
this is my setup..

[attachmentid=494529]

is it ok?...
or is there anything that i shud add in the tank...
currently there's 4 hermit crab in the tank

hi...
almost all of use Red Sea sea salt, normal blue salt is not advisable, however it is only for temporary.