Quote Originally Posted by Snagrio View Post
I've heard of salt testing hydrometers, what does that mean?
So with the salt test the hygrometer should ideally show 75% humidity. If it doesn't, you would know by how much the hygrometer is off or if it's adjustable, you'd calibrate it to 75%. I've only seem cigar hygrometer that can be adjusted. Unfortunately, I haven't seen ones for reptiles that can be calibrated.

You can google salt test and there's multiple instructions on how to do it.