The ceramic heat emitter is what is dropping your humidity. Being in Florida I assume you have air conditioning which is also lowering the over-all house humidity.

You could try using cypress mulch substrate or making a humid hide.

I basically just use a plastic container with a hole cut in the side and I put damp moss in it. Just make sure to change out the moss every couple days and that should help during a shed.

Other then that there isn't a whole lot you can do other than change to a tub