well i used an infa-red laser thermometer and seems like the temp. of the air inside the cave is around 85 and the temp of the floor is around 95. outside room temp. of 78

i was going to put a 50 watt heat lamp about 10 inches from the floor and about 6 inches from the top of the cave but i don't want to overhead her. are these UTH's supposed to heat up the ambient air in the tank or do they mostly heat up the substrate????