Brown inside of shell

[Mandiezxx2]

Help I have 4 hermit crabs that have been really active and healthy. The past couple of weeks I noticed they weren't being themselves. They have been hiding, not moving, not eating. The temp is between 70- 80 and the humidity is between 70-85. I have sand from the beach and a salt water dish of ocean water from the beach. Now I just recently bought a heater and placed it on one side of the tank and I noticed they hang right in that area. I spray it down like 3x a day to keep it moist and humid. And I also have a plastic cover with holes over top for the lid. My one has these large brown strips inside of his shell and he's also in a painted shell that he came with from the pet store. I have tried everything to get Him to switch but no luck. My other Hermie is a small one and its in a huge shell what is going on? Can someone please help me. I don't want to lose my shell babies I did just recently clean out there tank and notices one of the water dishes had a hole in it that made the bottom of the sand soaked. Can that be the issue? I have them in a fresh clean tank with new sand I hope they are OK.

[aussieJJDude]

http://www.hermitcrabassociation.com/ph ... 7#p1023377 <<< Already in the appropiate section.