Ok so I have a 7 month old regular corn snake. Hes in a 29 gal. I have a heating pad underneath it. My thermometer was one of the digital ones with a probe. If I bury the probe directly above the heating pad I get a reading of anywhere from 85-95 f. But if I let the probe just lay on top of my substrate it stays at 70-75 f. Am I ok with my temp, or should I make some changes?