Product review (1 stars): Does Not Work for White Dust from Ultrasonic Water Vapor
I purchased these because they were advertised to reduce the white dust that's endemic to ultrasonic humidifiers.  After a couple weeks of use, the dust was in fact made worse.  Furthermore, it caused the vapor to actually hang in the air so that there was a slight haze in the room.  I suspect the tablets are mostly salt as used in any water softener, but there is no ingredient list on the packaging or anywhere else I could find on the internet.  I suspect the tablets are only good for preventing the white minerals that builds up on surfaces INSIDE the humidifier (this happens with any humidifier type).  It does nothing for the minerals that are vaporized and put into the air that later settle down all over one's furniture.  Perhaps their performance is related to water hardness--but mine is not particularly hard.  Exceptionally disappointing-- I'm still looking for a solution.