View Full Version : Hygrometer Calibration Wierdness

03-28-2015, 03:48 PM
OK here is the situation:

I have 3 hygrometers:

#1 is a digital that I have checked with the salt test and it came out at 75% dead nuts. When I put this hygrometer in my humidor with 65% HF beads it reads right on at 65%.

#'s 2 and 3 are HydroSet II digital hygrometers which I recently bought. I salt tested both of them over the course of the past few days and have gotten them dialed in to 75% using the same salt test as I did #1. I am using this setup to do the test, a small glass dish with a clip-on lid that is airtight:

However, after calibrating them to 75% with the salt test, when I put either or both of the two new HydroSet hygrometers into the humidor right next to the one that I know is correctly calibrated, they both read 5 to 7 points lower than # 1. If I put any of them back into the salt test dish and wait, they all come right up to 75%.

Any ideas as to what may be going on here?

The Poet
03-28-2015, 04:42 PM
Any sufficiently advanced technology is indistinguishable from magic.

Oh, wait . . . maybe Clarke's Third Law doesn't work here. So what about his Second?

The only way of discovering the limits of the possible is to venture a little way past them into the impossible.

Hope that helps. :tu

03-28-2015, 04:51 PM
I'm only tellin' ya...

03-28-2015, 04:57 PM
I'm thinking I should just calibrate them to 65% in the humidor and be done with it.

Wharf Rat
03-28-2015, 05:16 PM
I'd suggest putting all 3 into your salt test setup at the same time.

03-28-2015, 05:51 PM
Not sure they will all fit, but I will try that. Maybe use a bigger dish.

03-28-2015, 06:41 PM
The salt test has the potential to be very inaccurate depending on how much water is used and unfortunately, it doesn't take much to skew it one way or the other. I would recommend the boveda calibration kit before guessing over setting the hygometers to match one of unkown accuracy

Wharf Rat
03-28-2015, 06:55 PM
Not sure they will all fit, but I will try that. Maybe use a bigger dish.

I like to do calibration in a heavy ziplock bag. If the hygrometer is adjustable with a knob, you can turn it without opening the bag up.

03-30-2015, 06:45 AM
Thanks to all for your advice. I got it worked out. The first one turned out to be off.

We can do anything. The impossible just takes longer...