Product review (3 stars): Limited life
This product enables me to continue using my Venta-Sonic humidifer, which is valuable to me.  The Aprilaire evaporation-type humidifier on my forced-hot-air home heating system sends 10 gallons of water down the drain for every gallon that it puts in the air.  In my area, the Aprilaire's wasted water can cost me hundreds of dollars a year, so I use the Venta-Sonic to significantly shorten the season and reduce the demand on my Aprilaire.  That said, my solution is far from perfect.  Our water has very high mineral content.  In a month of near-continuous usage (putting 2-3 gallons of water into the air each day), it isn't long before I start seeing white dust on my floors and furniture.  I have tried adding Holmes Humidifier Water Treatment with no adverse effect on the Venta-Sonic (though Holmes recommends against it), but with no real mitigation of the dust.