I use this with the Kenmore 12 gallon humidifier. Just a few capfuls of this per two gallon tank does the trick. Normally, evaporative humidifiers will get stinky after a few weeks of use. Not with this. Ditto with the scale. I have moderately hard water. No scale build up after two weeks of non-stop use. The filter has some build up, but not enough to stop it from working. I'll likely wash the filter in the dishwasher with a few cups of white vinegar to clean the dishwasher (bad hard water deposits every month) and the filter. I cleaned (wiped out) the humidifier today after two weeks of use. I'm sure that I would have had some hard water deposits if not for this product. It does not stink, so that is a bonus. This is NOT for use in the steaming humidifiers as that would cause you to breathe in the fumes from this product and it would not be a good idea. But for cold water applications, this works well.
We have been using this product in our humidifier for three years. It keeps the water clean and prevents any growth of micro-organisms so the air we breath inside our home is fresh and clean. It also helps with minimizing the formation of hard-water deposits and it was very desirable.
We always buy the water treatment by Sears, have tried some others but don't think they are as good.
This is my first time using a humidifier. I have read a lot of reviews from consumers about cleaning of the humidifier and how bacteria and mold can grow in the base. So far so good after about 3 weeks of use.