Product review (5 stars): If you own a VENTA, you NEED to purchase this.  It works ... and is very necessary!
If you own a VENTA, you need to also purchase this water treatment additive.  It keeps the water from getting that musty/moldy smell and helps prevents hard water/calcium from building up in the tank and fan assembly during the 2 weeks between cleanings.  The additive really works and is not just a gimmick.  I've been using Venta Airwashers for almost 10 years now ... so I speak from experience.

This is not a cleaner.  It is merely an additive that allows you to add water to the unit (without emptying and cleaning) for 2 weeks.  You will still need to clean the unit every 2 weeks.  I've found that submerging the tank/base, wheel and top (after you've removed the fan/motor) in the bath tub is the easiest/best way to clean it.  For a deep clean, I soak them in a bleach solution (as needed).