I see these things at my lps all the time. They say they can be used in high humidity tanks. I'm thinking of putting it on the back side of the tank and putting a sheet of foil around that. The UTH the used 10 gallon I bought came with under the tank is really only keeping the EE warm directly over it and isn't helping the ambient temperature at all. I can't use lighting systems at all even though I know that's what most of you use and recommend. I have to keep all my little fish tanks (5 gallons and smaller) and the hermit crab tank on this shelving system. This shelving system only gives me about 3 inches of clearance. My crabs buried but I know they're active because I see disturbances almost every day. I wonder if they're just cold and trying to stay warm? I'm worried about them. haven't seen them in a week or so now. I'm thinking of biting the bullet and buying a ceramic heat emitter and moving the tank to the top of the book shelf near it.