I do not use a digital hygrometer, I use one of those ones that are small and still costs you like $10 more than you should really spend on it. I will get a digital hygrometer soon, just using this for now. In my 20 gallon, I hot glued the hygrometer to the very top of the middle of the enclosure because I had tape on in before but she knocked it down every single night. I don't think I put it in the right spot.. soo.. where should I put the hygrometer? Like right on top of the subtrate, in the middle of the glass in the tank, on the warm side of the tank, on the cool side of the tank.... you tell me lol. I have it in the middle of the enclosure, hot glued all the way at the top so it's pretty close to the heat lamp, though, the heat lamp is on the left side of the enclosure and the hygrometer is in the middle.