HelP needed calibrating hygro/thermo.

[Susan10]

So I lost my entire hatch during lockdown because of my digital hygrometer and thermometer unit.
I have a few more eggs in an incubator now which are developing, but to avoid losing the entire hatch at lockdown again, I bought extra thermometers and hygrometers. I am attempting to calibrate 5, and every single one of them give different readings!!!! How do I know which one is correct? I figure I will have to keep returning them and getting new ones until I end up with two that show the same readings, but this could take forever! Is this just the reality of getting a reliable reading?!

 

[WalnutHill]

If you take a bottle cap full of kosher salt and add enough water to just scarcely cover the salt, and put the bottle cap into a ziplock bag, and then seal your hygrometer in the bag as well, after 30 minutes or so the hygrometer should read 75%. Adjust the hygrometer (if adjustable) or note on it what needs to be added or subtracted to reach 75%.

Calibrating a thermometer is a bit more complex. We really don't care if it's accurate at freezing or boiling, we only want it to be as accurate as possible at incubation temps. So use a medical thermometer, which is calibrated, and again mark the variation.

 

[Susan10]

The only medical thermometers I see are the ones in Walmart for babies where you have to push a button every time you want to take a temperature; no constant reading. Is that what you use? Should I stick the end through the vent hole of the incubator and press the button for the reading? How can I even be sure this is going to be correct? I've bought 5 thermometers and all have given different readings. This is insane!

 

[WalnutHill]

Medical thermometers, even relatively cheap ones, are reasonably accurate. Otherwise how could you tell if you had a fever?

Look at your incubator thermometer. Place the whole medical thermometer in the incubator...on top of the eggs is ideal but with the tip not touching a shell...and press the button. In a few seconds you will have a reading that should agree with your other thermometer. If not, note the adjustment for the ordinary thermometer, like "reads 4 degrees low", so you have a consistent point of reference.