I'm happy after 16 months of geothermal. We have dual vertical loops. I am thinking about buying surface thermometers for the internal tubes to gauge incoming / outgoing loop fluid temps. My research says that I can install the probe on the outside of the pipe/tube and then insulate heavily over that probe, and get a very close approximation of the ground loop fluid temperature. Of course, it's all data unless I know what temperature the loop SHOULD be reading. Does anyone have any guidelines on what the incoming loop temps should be; and thoughts on where it would be best to install the sensors? Thanks.