I have noticed when I turn the lights out in my tank the humidity goes up several degrees. Unless you are going to use an alternative heat source (heating pads) then you kinda need those on... so I'm not sure either. I bought some Sphagnum moss today. I'm going to try wetting that down and setting it around her hide to see if that will help with the humidity. She's getting ready to shed so I need it up a few degrees.