Product review (3 stars): No Rocket Science!
We own an Air-O-Swiss AOS 7135 ultrasonic humidifier. For a couple of weeks now, the machine indicated, through its warning light, it required cleaning. Initially we bought Air-O-Swiss EZ Cal Cleaner / Descaler. Didnt do the trick! Cleaning light remained on. Thereafter we replaced the demineralization cartridge (and contents.)  The item under review here.  Still no change. Even after following the instructions to the letter and cleaning with specialized brushes, our humidifier wouldnt extinguish its cleaning light. So, last resort, EZCal Pro.  No change.  Cleaning indicator remains lit.  So, our humidifier is presently running with the irritating little light on, but operating as it should be. None of the Air-O-Swiss maintenance / cleaning products did wonders in our case. Im rating this product average (3 stars) as I understand its intent (no rocket science) and thus envision it does what it is intended to do.