How do I Calibrate My Hygrometer?

In order to calibrate your hygrometer, you will need a Ziplock bag, salt and a small shallow open container, like a bottle cap.

In the shallow container, place about a teaspoon of salt and add a few drops of water to get it wet. Don’t add too much water, just enough to get a moist pile of salt.  Remember, you don’t want a salt water solution, just damp salt.

Place the container in the bag along with the hygrometer. Close the bag with some air trapped inside and let it sit.  Allow this to stabilize for at least 6 hours (don’t rush it).

After it has stabilized, check the hygrometer reading without opening up the bag.  It should be exactly 75%.

If not, you can simply adjust the reading by turning the dial on the back of the hygrometer with a small screwdriver, if your hygrometer permits.

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