HCA: Hermit Crab Association

Hi, I'm Mandi. I've got a total of 4 hermits in my home, two in each 5g tank(and after going thru this forum realize it's too small). They are all about 3 inches when standing. In my oldest daughter's tank there is Athena & Aphrodite. In my youngest daughter's tank we have Gary & one yet to be named. I can't get any pictures to load due to size.

Now I have lots of questions but will post them in the right sections, but my urgent issue is this... My parents bought the girls one hermit each on vacation two weeks ago and I knew they are social so Thursday i spent a lot of cash on two 5g tanks, huts, uths, shells, bowls, climbing sticks, sponges and two more crabs. I did not realize they need to go under to molt. I only have about an inch of sand in each one. Now Gary has been switching shells constantly and I noticed a water sac, the one that means he needs to molt. What's going to happen if I can't get the extra substrate before he molts?

"Judge a man not by his answers, but by his questions"

Assuming you're using playsand and not calci-sand* (sold as "reptile" or "hermit crab" sand), you can gradually add a bit more each day. If you don't pack it down and Gary digs in, he'll be fine. If the substrate isn't deep enough, he may do a surface molt. That isn't the end of the world but he'll need some TLC and protection from his tankmate.

*Calci-sand is not good for hermit crabs as it does not retain water well and can compact around a tunneling or molting crab, essentially suffocating it. Old fashioned playsand ($5 for a smallish 50lb bag at Home Depot/Lowe's) can be mixed to sandcastle consistency, is excellent for safe tunneling and will keep the humidity in the tank at a higher and safer level than calci-sand.

Do you have a picture of the water sac?