Hi all. I just posted to a thread that was looking for info on how to calibrate a hygrometer. (https://www.backyardchickens.com/forum/viewtopic.php?id=615625) Rather than hijack that thread, I thought I'd post new. Alienchick posted a really useful method for calibration, using salt and water. This tests the accuracy of the hygrometer at 75% RH, at room temperature. Is hygrometer calibration something that comes up regularly, and is it important to you? Would it be useful to have additional ways to calibrate for other humidity levels?