Opposing probe numbers

[dakoop]

Looked at my apex when I got home and my two temp probes are in disagreement. I had two so I had a backup if one failed, but what do I do when both are acting up? Any advice?

 

[tzabor10]

Use a bulb thermometer. And check for probes out of the water

 

[bblumberg]

I would get a NIST traceable thermometer to ascertain which of these readings is accurate. They are relatively cheap from Amazon.

And +1 on tzabor10's idea to make sure that both probes are in the water

 

[vetteguy53081]

Use a manual thermometer and see which probe is closer to your readings

 

[dakoop]

Return pump stopped which is what the separate readings. One in tank and one in sump

 

[X-37B]

Get a temp strip and attatch it to the side of your tank. You will be surprised how accurate they are.
Mine reads the same as my aqualogic controller, Hanna monitor, and my old mercury thermometer, lol.
I have used an old mercury for years as a backup. I have several but my one that reads from 66-80 is my favorite.