Product review (5 stars): A must-buy with the Honeywell Germ Free Cool Mist Humidifier, HCM-350
A must-buy with the Honeywell Germ Free Cool Mist Humidifier (HCM-350). Our first filter turned pink and hard with mineral deposits within about 14 days. So I bought this Humidifier Bacteriostatic Water Treatment to try and extend the life of the filter. BIG difference. The second filter has been in use over 30 days with only minor signs of wear. I think we should be able to get 2 months now before changing the filter.  You only need a very small amount of the treatment, so this bottle should last several winter seasons.

Tip - Flip the filter each day - this helps to keep the filter clean and last longer.