Product review (5 stars): Works Great
This stuff is great.  I've had problems in the past with my humidifiers getting algae or other "gunk" in them.  I only use my humidifier in the fall/winter months when the air is really dry (I live in the south, so humidity isn't a problem the rest of the year).  I've used this for two years now, and I haven't had any growth or issues.  It's super easy to use, does what it's supposed to do, doesn't smell, and one bottle lasts forever (I haven't used even half my bottle yet).