I like to keep my humidity as recommended, between 50-60%. I also had to put holes into the tubs and I wanted enough where the air is exchanging. Stale air and humidity breed bacteria. I only have to mist the tub once or twice a week. Once warm weather hits again the furnace won't be drying out the air so much and I won't have to mist as much. I just know aspen is prone to mould and I didn't know if it was safe to mist it directly it just the sides of the tub. I have only been using it for a month or so.