Keeping a temp gradient in an arboreal cage is tricky, depends a lot on the type of cage. My ambient daytime temps for ATBs was always about 84 degrees, slightly cooler in the corners of the cage than under the pearlco ceramic heaters where it would keep about a 90 hot spot. That's using 2' cube cages with pearlcos on top and flexwatt underneath.A night time drop of 5 to 10 degrees allows them cool time. Worked for me for many years. Hope this helps