So I have a few crabs in a 10 gallon crabitat. Glass walls, mesh screen, plastic wrap on top of half of the mesh, the other half has the light fixture with a 50w infrared bulb, and a uvb 13 w CF. I have a 2 layer substrate, sand eco earth, and some type of moss. I also have two dishes, the freshwater dish is larger and has a sea sponge, the other is a small saltwater dish. Given all this, I seem to have tremendous difficulty keeping humidity high, above 70 even for a while. I'm constantly having to mist. I seem to be having the most difficulty when the infrared light is on. It runs very hot and puts the crabitat up 8-10 degrees. Is the light too hot? Should i downgrade to a 25w light? I have not verified that my hydrometer works, its a cheap ZooMed analog one, but it does go up with a noticable humidity increase, but I don't know if that means its working.

I'm out of ideas, so I could use some help, I really would rather not have my crabs suffocating half the day while I'm at work and can't mist.