3 Different temperatures!

[coops784]

New to smoking this past Summer and to this board as of today!  Great information and I'm looking for some help regarding temps.  I fired up my smoker today with 25 degree temps to see how it would react....getting it to temp isn't a problem however I just can't find which one is reliable.  My door temp reads 175, my little stand thermometer sitting on a rack read 225 and my electronic probe thermometer laying on a rack read 318.  My gut tells me my probe is the one to watch however any help would be greatly appreciated.

 

[boykjo]

Calibrate the remote probe. Ice water bath should be 32 degrees and a water boil will be 212 depending on your altitude. Forget the others. When placing it in the smoker stick the therm through a potato so the tip protrudes out and place it near the food

Joe
 

 

[coops784]

will do thanks, what does the potato do just hold the thermometer off the rack for more accurate temp or does it serve another purpose?
 

 

[boykjo]

Just holds it off the rack