Product review (4 stars): I guess they help
I have used these for years in my humidifiers.  I guess they work.  I guess I dong really have any evidence either way.  I never have to actually change my water, so I guess that could be something good to say about them.  I still have to clean out my humidifiers every so often due to buildups, guessing that is stuff in the water though.  I so usually use these for 1.5-2 months total instead of just one month.  Adding a gallon of water or more to each humidifier every day.

I ordered the Amazon two pack, which is exactly what it says, 2.  You get a total of two inserts.  The wording on the three pack says 3 packages of 2.  So Im wondering if you get 6 total, or if there is a typo.  That is why I ordered the two pack, if it was 4 it was a awesome deal (two packs of two) but if it was just two inserts (which it was) it was still a decent value, but nothing to praise Amazon over.  If someone knows of the 3 pack, please comment.  I plan on ordering it in a month or so anyways, to see.