Product review (5 stars): Easy-to-do cartridge refill granules
Your AIR-O-SWISS humidifier requires a constant de-mineralization container inside the water tank. They come already filled OR you can fill them yourself. The economics are in favor of the refill method. Either way it will require a 24 hour soak prior to use. It is also incredibly easy to dump the old granules (trash or disposal), insert the spacer, add the granules, extract the spacer, screw on the cap and add to the container after the soak to "swell" the granules. Takes up less space to have these granule packs around then the same number of filled cartridge, too.