Product review (1 stars): Not as good as the bagged stuff.
I have used only one of these cartridges, but it kept shutting down the humidifier.  When I called the help line (1-800-336-0326) the nice lady insisted that I try to remove a few tablespoons of the granules and try it again.  This made the unit run longer between stops, so I removed almost half of the granules, but it still stopped.  This updated product seems to be self-clogging.  I put the old style refill granules in the cartridge and now it works fine again.

Hint to refill: put a paper towel in the center opening of the cartridge and pour the granules in around it.  When they get to the top just tap the cartridge up and down to settle the granules.  Then remove the paper towel.