Ebo Jag Heater Not Reading Correctly

[Pinnochio5]

Hello all,

 

I have had my 50W EboJager heater in my 10G for about 5 months. I always wanted my tank to be around 78-79F. I have the heater on the lowest setting possible, 65F, and the best it gives me is 80.5-81F. Anybody else having a problem with their heater adjustable knob?

 

Thanks