I have an ongoing battle of mash temperature between by digital thermometers and my analog thermometers. My kettle has a thermometer about 3 inches up from the bottom and it might read 160 degrees, but my digital reads 151 even when I stir it REALLY well. So I get my other digital thermometer and it is the same 151. I get the floating thermometer I never use and it reads 160. WTF??!!! Any suggestions? I'm using a Bayou Classing 8 gallon kettle, and most recently brewing a RIS. Which should I temp use?