Apex temperature not correct?

[Jaylivi1212]

My apex controller is saying my water temperature is 66 Degrees when my standard thermometer is saying 78 Degrees.

 

[Jaylivi1212]

When I also sign into the fusion webpage instead of apex.local
It says
Probes
ORP31
pH7.49
Salt1.00
Tmp20.5

 

[JustSomeGuy]

Sometimes you have to log into fusion to manually calibrate the temp sensor. I have had to do it once. So far after the original calibration. I use 2 thermometers to check temp before calibrating to a new temp.
Always a good idea to leave some type of thermometer in the tank at all times so you can catch things going amiss before things get worse.