Product review (3 stars): Demnral Granuels Pk/3
Had this item many times before.  Run my humidifier all day.  Deminral performs fairly well for a few weeks, then white film covers all again.  Have used distilled water without Deminral and find that much better.  However, purchasing gallons of water and storing it gets tiresome and expensive.  So...I switch between both solutions to prevent the white film.