The Demineralizer Cartridge in your Air-O-Swiss AOS 7131 Cool Mist Ultrasonic Humidifier should be replaced or refilled after every 2 to 3 months of use.  The recommended time interval depends on the hardness of your water since the demineralizer captures minerals like calcium and magnesium from your water.  If your water is exceptionally hard, meaning it has more minerals in it, you may have to replace or refill the demineralizer more frequently.

You can buy a Demineralizer Cartridge that completely replaces the original cartridge that came with your AOS 7131 Cool Mist Ultrasonic Humidifier or you can easily refill your original cartridge using the 3-Pack of Replacement Granules.  The refill option is more economical than replacing the entire cartridge.

We recommend using an Ionic Silver Stick (ISS) with all Air-O-Swiss Ultrasonic Humidifiers.  The ISS is standard on models AOS 7135 and AOS U7142 and was standard on model AOS 7133 until Fall 2007.  Currently models AOS 7133 and AOS 7131 are sold without the ISS, but we highly recommend using the ISS with these products.  The ISS kills over 650 types of bacteria and viruses, so you can be confident that the moisture you are adding to your room is clean and healthy.  The ISS should be replaced after each year of use.

The base of your Ultrasonic Humidifier should be cleaned every few weeks.  We recommend using EZ Cal Descaler and Cleaner to make the cleaning process easier.  EZ Cal is sold in 3-packs of pre-measured, ready-to-use powder.

	Demineralization Cartridge Cartridge should be replaced or refilled every 2-3 months of use.  See replacement granules below as a more economical/environmentally friendly option. (Air-O-Swiss part #AOS 7531)	$12.50
	Replacement Granules, 3-Pack Granules can refill demineralization cartridge instead or replacing the entire cartridge.  Replace every 2-3 months.	$19.00
	Ionic Silver Stick (optional - replace every 12 months)	$29.00
	EZ Cal Descaler and Cleaner, 3-Pack Optional, but makes cleaning your AOS 7142 easier. (Air-O-Swiss part #A7417)	$6.99
	1-Year Ultrasonic Replacement Bundle Contains one Demineralization Cartridge, one 3-Pack of Replacement Granules, and one Ionic Silver Stick (save $8.50 vs. buying the parts separately)	$52.00