This dehumidifier from Hydrosorbent comes with an inbuilt recharge indicator. The indicator is at first orange in color, but it turns by itself clear when it requires a reactivation. Both of those have a electronic humidistat to regulate and maintain the humidity all the way down to 30% RH. Everything https://bookmarksusa.com/story20878359/the-basic-principles-of-dehumidification-in-cold-stores