Glue?
Don't put any cigars in it.
Take it back to where you got it, get something else.

It's "hygrometer" not "hydrometer".
.

You need a faster spell checker !

Know it all strikes again!

Good job, what would the interwebs do without you.

Hygrometers that come with humidors are generally terrible. Season your humi before you put anything in it. Makes it easier to diagnose... human nature says ."maybe it's something I put in it", but if you didn't put anything in besides humi sh--., nothing to blame it on.

What never seems to be mentioned when I read about salt testing a hygrometer is temperature. This salt thing is 75% at 70 degrees F. If the temperature when you take your final reading varies from 70 degrees it should be like this;

TEMP should read RH
69 77%
68 80%
67 83%

71 73%
72 70%
73 68%

Around 60 degrees F the amount of moisture in the bag used for the test will be about 100% leaving you with condensation in the bag. I am not sure why they never mention temperature when discussing the calibration test. If your hygrometer in the humidor reads 68 degrees and 75% RH you are dead on. If it reads 73 degrees and 63% RH you are dead on. If your temperature is below 70 and your RH is also below 70 you are dry. If your temperature is above 70 and your RH is above 70 you are moist. And remember the hygrometers are generally +/- 2% accurate to start with.

.
Get one new Boveda at your desired RH. Get a gasketed airtight transparent plastic container, not too small or the Boveda will keep the RH inside a few points too high which will throw your calibration off (they claim it won't, but I've tested it multiple times, and it does), about the size of a shoebox or just a little bit smaller is good. Toss in the Boveda pack and one or more Western Caliber IV units (which are excellent), positioned so that you can read their displays through the container without having to open it. Wait 24 hours, then begin taking multiple RH readings from them, writing them down in a log. After you get a healthy set of samples, average the deviation from the target RH for each unit to arrive at how much to add or subtract to make it maximally accurate most of the time. Use the units' calibration function to add or subtract the right number of points to/from each unit, where needed.

Works perfectly and it's very easy. No salt, no mixing/ratio questions or uncertainty, and you're calibrating at your real-world storage RH, not at 75, an RH you'll never actually want to reach.
.