Use a temp gun (or thermometer if temp gun is not available, but temp gun preferably) to measure the temperature of the the cage floor above the UTH, and adjust the rheostat until that surface is consistently 88-90* or so (hot side) or 78-80* (cool side).
Originally Posted by Sunnieskys
Make sure you measure on the glass without substrate. As said above use a temp gun. Do not measure on the substrate. Move the substrate and measure the glass.
They said it all. There's no set temp, it's trial and error and different for every situation.