Calibrating Thermometers?

[Johnd651]

Just wondering if anyone calibrates their thermometers? I used to using an ice bath.

Just noticed yesterday that the Imkbird was off by 1.2°F compared to every other thermometer in the house. I was able to adjust the inkbird, but it made me wonder which one was really correct?

I know for reefing it's about consistency, which is why I went with an adjustment against the previous thermometer.

 

[Jay Hemdal Verified Community Expert]

Just wondering if anyone calibrates their thermometers? I used to using an ice bath.

Just noticed yesterday that the Imkbird was off by 1.2°F compared to every other thermometer in the house. I was able to adjust the inkbird, but it made me wonder which one was really correct?

I know for reefing it's about consistency, which is why I went with an adjustment against the previous thermometer.

Ice baths or boiling water are often mentioned for calibrating thermometers because of known values (barring differences with air pressure) for those two events. I’ve always wondered though - that assumes any deviation is linear across the measurement range….and I’m not sure it always is.

I prefer a “consensus” approach, using an ASTM standardized lab thermometer as a starting point, in the range that it will be used at, and use all my thermometers against each other and adjust or discard any outliers.

 

[Johnd651]

Ice baths or boiling water are often mentioned for calibrating thermometers because of known values (barring differences with air pressure) for those two events. I’ve always wondered though - that assumes any deviation is linear across the measurement range….and I’m not sure it always is.

I prefer a “consensus” approach, using an ASTM standardized lab thermometer as a starting point, in the range that it will be used at, and use all my thermometers against each other and adjust or discard any outliers.

ASTM E2623-14 standard for calibration is 0, 50, 100, 200C. The 0 is with an ice bath, and the other three are with an oil bath. Reef tank temp sits about half way between 0 and 50C, but checking with ice bath and boiling water for a test thermometer and then comparing is probably sufficient.