Did you calibrate them ?
Sent from my SM-G900P using MonsterAquariaNetwork App
You only have to calibrate if the temperature isn't what you set it to, right?
I did calibrate the third one and it was working fine for a few months and then the temperature kept rising and then it would steady. Sometimes it would fall and then steady. It's at a constant 82 right now but it's set at 73 as mentioned. There's also condensation in the glass...did a google search on it...some said it's a red flag, some said its fine but I'm not risking it.
The two that were stuck, I had in the tank 24 hours to see if it would need calibrating but the light wouldn't go off and and the temperature kept going up.