Do you PH your humidifier water? I've always used de-chlorinated tap water in my humidifier. But my next grow I am going to ph that water just to see what happens. I've never seen anything mentioned on this subject. My tap water is close to a ph of 8, so am I not technically giving them a non-stop foliar spray in that range?
. Ultrasonic humidifiers apparently suspend all/most included contaminants so you may be right it’s different from a steam humidifier where the produced vapors would be more pure. You know your going deep when a google search ends up confusing me even more.