My ambient temp is around 85 during the day. Remember though my girl is in a 20 long until I get the brain power to build her a nice enclosure. I would put the probe right over the uth . Bury it into the substrate. The only time I ever saw my girl burrow was right after I fed her the first time in months, and he had heat and water. I had to really beg for my friends who were watching her for me to give her heat. She is in her hot hide and has been for a few days now but not burrowed down. I need to go today and get her some food. I need to haul her out of the hide and measure her lol. Hope shes in a good mood. Balls do like to be underground so maybe the light is too bright, or he doesn't feel secure enough. I don't know I'm not there and can't see everything myself.