Humidifier Cleaning Fish effectively reducing surfaces, this tank cleaner is free from harsh substances. Offering continuous cleaning, it inhibits dirt growth and prevents slime buildup in water. Utilizing the proven Protec Cleaning Cartridge, safe for drinking water filters, it eliminates objectionable smells and tastes. Long-lasting, it cleans for 30 days and is compatible with most humidifiers, vaporizers, and steamers. With gentle cleaning action, this tank cleaner is as mild as water on your humidifier surfaces and components.