Product review (2 stars): Cheaper than catridges - but not effective
I've observed this product very closely over a year's time and consider myself highly knowledgeable. That is not bragging, just the result of having to dust inside my closet, and hating every second of it.

I hesitate to say nothing's happening but I'll just say, after using the more expensive (and also not effective) cartridges for a while I decided to try the granules and change them even MORE often.  I changed the granules once every three weeks - there was white mineral dust before I bought these, there was white mineral dust after I bought these. Was there less as a result - maybe a small fraction less dust - but there was still a substantial amount to deal with (including finding dust INSIDE a printer that was INSIDE a closet).  If you want to know what effect the granules are having/not having, you can buy a meter to measure the mineral content of water for about $15.  I bought such a meter but only after I gave up and ditched the granules for a reverse osmosis system (I wanted to make sure there were zero minerals in the water, a.k.a., no dust).

I love my Air-O-Swiss humidifier - but if you want to eliminate the white dust, this is not the way - invest in a reverse osmosis system. Too bad Air-O-Swiss doesn't make one.

PS: If you ARE using these, ignore the diagram - to get the old ones out of the cartridge, unscrew the cap, turn the filter upside down and run it under water (collect them in a pan - don't flush them down the sink; strain the water and throw them away).  Pour the dry granules into a 12 oz. cup, soak them, and after they've soaked 24 hours, pour them/the water into the cartridge (the water will drain through the bottom filter).  That way they'll distribute evenly without getting all over you/your counter and driving you insane. You can still use the foam piece to keep them from getting in the middle part of the cartridge.