Product review (5 stars): Great stuff for regular winter humidifier users
Great stuff for regular winter humidifier users.  Use it every fill, really seems to extend the life of the fairly expensive filters (possibly up to 2x), and definitely reduces the deposits and other junk in the reservoir when I clean it weekly.

Interesting side note, I've been buying this for a few winters now, and it always calls for two cap fulls per 2 gallons.  I can't be certain, but I swear this time they've made the cap twice as big in the latest bottle, which would be an interesting way to get people to use more without raising prices.  Buyer beware I guess, although since my humidifier is 4 gallons per fill, I can just use 1 instead of 2 caps per full fill.  Still, like this product a lot.