Potential causes for white powdery substance coming out of humidifier:
Humidity level in home/room can contribute to this. When using the humidifier on high setting, the mist can look like white powder. We suggest adjusting the setting to reduce mist output and using the unit on low setting unless the room is extremely dry.
Some chemicals used in safe water treatment could become white powder as the water vaporizes. This is not a humidifier malfunction. To resolve this, use distilled or filtered water instead of tap water.