I have found that Kitty likes his warm side to be about 93, sometimes higher and the cool side about 85. He does that best at these temps. You may want to up yours a bit. I started out with an undertank heater only and it wasn't warm enough. His temps were about what yours are, but he got a RI (mild case) so I learned and raised his tempuratures, no troubles like that since. It is harder to keep the humidity up at the higher temps though.