My temperatures are usually fine. No fluctuation, (no more than .2 degrees. ) steady and good. I held him for a few minutes as his tank warmed up. Its still slowly raising (I added a "back up" lamp. Its a desk lamp that gets pretty hot (112). I unfortunately don't have a space heater. But while I was holding him I dropped his heat lamp lower into the tank (to warm it faster) and that seemed to have worked. Ambient is up to 76.6.