Product review (1 stars): Graco Humidifier Replacement Filter for 4.0 Gallon
Not sure what's going on with particular brand of replacement filter... I run my Graco Humidifier about 9hrs at a time - and the level of water consumed from the tank is not noticeable - I'm talking day 1 out of the box.  With the other filters I have used (not the one I am reviewing), I would easily go through almost an entire tank.  I won't be buying this brand again.