I just tested the digital hygrometer and it reads 7% too low. Yesterday I got a new hermit crab named Lou-Lou and put her in the ISO. I read you should start off with the humidity of the pet store the hermit crab was in and every week increase it by 5% until it is 75%. I'm guessing the humidity was about 60% because there was only a sponge in the tank, no fresh or salt water. I read the digital gauge and it said the humidity was 76%. That means the real humdity is 83% which is too high for the main tank, let alone the ISO. I took the lid off and took away the sponge but it didn't change. I'm really worried about Lou-Lou. What should I do?