i've been a snake owner for over 20 years and for the first time today i had a thought. what is the relationship of air temp to surface temp? do you check ambient air? surface? both? i take my temp with a digital thermometer about 1" above the subsrate in the hot spot which is over the UTH and under a lamp. its generally right at 90. the probe fell off the side of the tank and was laying on he ground earlier and it read over 100 and thats what made me think about this. since surface temps are always higher than air temps, what is the proper surface temp?