Product review (1 stars): Terrible Product
I have been using this product for over two years, and coincidentally have been replacing filters every ten to twelve days, on two separate  humidifiers. The filters would develop a sort of polluted water stench, and only a cleaning, and a new filter would rectify the problem. Well, needless to say, it was getting pretty expensive. I tried cleaning the filters, and all types of experimentation to rectify  this problem. In all fairness, I called the filter company on two occasions, and explained what was going on, and they sent me five replacement filters, each time at no cost. This year, after buying $120 worth of filters to get me through the winter, and being all out of tricks, I decided to try laying off this additive, and lo and behold, problem solved. No problems, I don't know what is in this additive, but in my case, the filters are being destroyed by it, way before they should be replaced, and now I am getting a minimum of 30 days, out of my filters, which isn't great, but much better than before.