I use a Vicks Ultrasonic Humidifier and get the “white dust” everywhere. White dust occurs when the minerals in tap water disperse into the air. Boiling the water will not remove the minerals. Distilled water has no minerals but can get expensive after a while. The filter in the Vicks unit is supposed to prevent the white dust but the filter has to be replaced often. I now use a vaporizer for my chameleon in my living room and the Vicks for the ones in my basement.