Calibrating different Eheim Heater

[Anemonee]

Does anyone know how to calibrate this kind of heater? I have the one with the red ring currently but received this with a tank just purchased.

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[Uncle99]

I tried and could never get it right.
I went with two digital thermometers, they run only .2 degrees F different.
Just easier for me

 

[thegrun]

How as in how do you make the adjustment (you rotate the bezel indicator tot the correct temperature) or how do you know what the true temperature is (I use a certified lab grade glass thermometer).

 

[Uncle99]

How as in how do you make the adjustment (you rotate the bezel indicator tot the correct temperature) or how do you know what the true temperature is (I use a certified lab grade glass thermometer).

I think your use of the certified thermometer is very wise and accurate.