I would suggest doing a little searching on the forum. Many others have had similar issues. It sounds to me like your hygrometer needs calibrating, i would suggest the salt test. If that is not the case then i would consider RH beads as they absorb excess moisture as well as maintain the RH.

By the way, welcome to board. There is a ton of info on here so be sure to browse the site and let the search tool become your friend. Good luck with your humidity issue.