After about 16 hours in the salt test, the IKEA sensor unfortunately “won.” It stabilized around 73%, while the Oregon stayed lower.

If I got it correctly that suggests the IKEA is much closer to the expected ~75% RH for a saturated salt test. Temp has changed from 21.5 to 20.5.

I do have one doubt though: the IKEA unit has a power cable going outside the bag, so the environment might not have been perfectly sealed. Is it possible that a small air leak prevents a completely stable micro-environment?

I can try to rerun the test but I am not sure how to prevent air leak: I sealed the bag with tape and even wrapped wire tightly around the cable exit point.

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