Humidifier leaves white dust on furniture and surfaces.

Safety: No internal repair is required; this is a water quality issue.

• Switch water source: Use distilled or demineralized water instead of hard tap water.
• Install cartridge: If your Medisana model supports it, install or replace the demineralization cartridge in the tank.
• Reduce output: Lower the mist output setting to reduce airborne mineral carryover.
• Clean surfaces: Wipe affected surfaces with a damp cloth to remove existing dust.