Product review (5 stars): A Very Good Filter That Does The Job For A Long Time
This humidifier filter really does a great in keeping the atmosphere moist and filtered.  It's expensive; however, it lasts for up to six months, so it's worth the money.  I will say though; I use a humidifier Bacteriostatic Treatment in the water, which IMHO, truly helps in keeing the filter cleaner for longer periods of time.  This treatment assists in controlling bacteria & algae build up in our evaporative humidifier.  (Essick Air Humidfier Bacteriostatic Treatment)