Product review (3 stars): It can stop flow of water to humidifier
Sometimes when I use these refill pack, the water would stop flowing through the demineralization filter canister when the water tank was half full or more, so the humidifier would not work. I found that if you tap the newly refilled canister on the top end (the side from which you filled it) so that the granules move away from the screen at the bottom of the canister, it flows better.  Even though the manufacturer does not say to do this, after I empty old granules, I soak the empty canister in the Air-O-Swiss EZ Cal descaler to clean the screen on the canister to reduce the chance of any slow flow.  I then thoroughly rinse the canister before filling it with a new package of granules and soaking it for 24 hours as directed.