jd50ae said: Do a search on RH and hydrometers and distilled water.
VegasFrank said: @IndustMech I have the exact same Rubbermaid container and the exact same hygrometers. This is how I calibrated mine also. Funny thing I noticed though. I let it set for overnight and in the morning the RH was 75 on all of my units with a 75% boveda pack in the box. I left them in there and when I came home from work, they were all reading 78%. Now which number do I trust?