HCA: Hermit Crab Association

I have 3 hermit crabs, 2 of which are in a ten gallon and the newest, in an isolation tank.
I am wondering, what do I need to have in my ten gallon for happy, healthy hermit crabs?
Here is a list of what I have in the tank;
One fake plant, 2 coco huts, 3 large shells, 2 sponges, 2 dishes of water (one fresh with a sponge, one salt, no sponge), 2 dishes of food, a thermometer and hygrometer and I use a mister daily.
What am I missing?

Have you had a look at the 'basics' care sheet? Everything you need is outlined there. And I'm pretty sure the photo is of a ten gallon tank too!

You don't need sponges for the water, they just harbor bacteria.
What are you using for substrate and how deep is it?
You will want 3 to 5 extra shells per crab - be sure to look at the 'shells' care sheet so you get the appropriate type of shells.

Thank you! I have not looked at the care sheet yet!

Here's the link to all the care sheets:

https://www.hermitcrabassociation.com/p ... .php?f=120

Thank you!