Surface temp question

[LiVZ]

I understand that the recommended basking spot temp is a measure of the surface temperature. However I've found that, based on different surfaces used, the temp can fluctuate by tens of degrees. How can you be certain that your temps are safe?

For example, suppose you are using a black rock as a basking spot with a measured temp of 130F (too hot). Then, without changing any of the lighting, you swap the black rock with a white rock and measure a temp of 100F (cooler because, more heat is reflected). Is the second setup safe? Even though the surface temp is okay, a basking dragon would get the same amount of heat directly from the bulb as in the dangerous setup.

 

[BadCon]

IR Thermal gun, measure directly on the back of the bearded dragon....determine optimum basking temperature .
Seriously though, the surface temp requirement is to prevent burns and accidental overheating should they absorb too much heat from the surface they are on. Other then that, the dragon can thermoregulate on their own...so don't worry too much. As for the minimum heat, if it can heat a surface to 100-105, regardless of what that surface is, then it can get a dragon to optimal basking temperature. Remember, they themselves aren't all that reflective and can alter their color slightly to aid in basking and heat retention.(lighter/darker). So a dragon is probably absorbing a good deal more heat then whatever surface they are on (as nature probably intended).