Hermit crab molted, and then died?

Question
QUESTION: About three weeks ago my second largest crab pulled a surface molt. I put him in an ISO tank where he has remained ever since. I began to get worried, since he has taken so long to finish his molt, that he had died in the process. Leaving that worry behind, I decided to give him a few more days. And then, my smallest hermit crab pulled a surface molt (this was about 1 week ago) so I put him in the ISO tank as well. Today, 1 week later, I decided to check up on the crabs, and both have their exoskeletons out and laying beside them, but this is where the real worry begins: both crabs can be seen in there shell, and they are both chalk white and not moving. It's almost as though they've molted a second time in their shells, but I fear this time they have died.

Are my hermit crabs dead? Again, they are chalk white and not moving in their shells, and I know its not their exoskeleton because their real exoskeletons have fallen out onto the substrate.

Any help would be appreciated, thanks!

ANSWER: Do they smell?

What type of food and water do you offer?

What is the humidity/temp in the ISO tank?

---------- FOLLOW-UP ----------

QUESTION: I've been smelling the tank and all I smell is chemicals. No dead fish. The water I have been giving them is dechlorinated, in a big dish in the middle of the tank. Then temperature is about 82 degrees Fahrenheit, but I have yet to find a humidity reader (I read that as long as you have a big enough water supply in the tank it will keep the air moist enough for them, but I suppose I should make sure I pick up a humidity reader). As for food, I tend to feed them fresh vegetables, rice krispies, crushed nuts, raw shrimp, and the crab food that I bought when I got them.

When my second one molted, I transferred him into the ISO tank, and at that time he was still soft and bright orange. Now there is this blue-white thing hanging out of it's shell, it looks kind of crusty. Unless this is some kind of extra molt or something, it looks so dead!

Do you think I should throw them out, and if not, how long should I wait before throwing them out.

Thanks for the reply!

Answer
Do not throw them out unless you are getting a very fishy smell coming from them.

You can buy inexpensive hygrometers from walmart in the home section for $6.00. Just keeping a good water supply will not keep their tank humid enough.

Everything looks good on your food list but the rice krispies. They don't need that refined sugar and processed flour.

Make sure you are also offering ocean style salt water.