My Crabs Hate the Sand

[irl]

I am new to keeping hermit crabs. I just changed from gravel bed (due to researching what's best) to sand. I noticed 2 things.
1. the crabs have started climbing and won't dig into the sand like they did into the gravel.
2. it's harder to keep the humidity level up in the tank than it was with the gravel, and I'm afraid of suffocating my friends.

Now what?

[Wai]

Are you using a glass tank with a lid? It's normal if they don't want to dig. Have you gone through some of the tips in the Crab Care section too? Sand is a desiccant and although it will absorb some humidity from the air, it is a better substrate as the hermit crabs can moult in it (i.e. not die), unlike with gravel.

[irl]

Thanks! I did go through the crab care section and will continue to review it. I have acquired an under-tank heater and a heat lamp for my buds, I noticed they are WAY more active since I've kept the humidity (I wrapped the grated top in plastic) and temp up, so I am encouraged. I will try to loosen the sand for them so it's not so compact.

[irl]

With 80% humidity and 75 degrees, how do you keep mold from growing in the sand?

[Wai]

Make sure that any uneaten food gets removed from the sand. Maintaining humidity is a balance between keeping the top of the tank sealed enough so that it can hold humidity, but still allowing enough air flow so that the hermit crabs don't suffocate and help reduce mould growth. Mould develops where environments are humid without enough air flow. Furthermore, it's a good idea to either do a deep clean of the sand or simply replace it once a year. I have not been replacing my sand annually, but I haven't had issues with mould. If the surface looks a bit grotty eventually then I just replace the surface one inch or so of the sand.