I would just get a new one. Right now, my Nat Geo thermo/hygrometers are my favorite National Geographicâ„¢ Digital Reptile Thermometer & Hygrometer | Humidity & Temperature Controls | PetSmart I have not seen good reviews on them though, so I must have gotten lucky. I have used all living things therm/hygrometer and the exoterra ones, they do not seem to measure humidity correctly after a short time. Both of them would get stuck at 99% for days at a time, and considering I have ventilated tree frog vivs, I know that cannot be correct.