Desert Spring AutoFlush System (DS-AF15) - US$
I bought an auto flush valve for my Dessert Spring humidifier. It failed. I was sent new one.
If you have a water control valve, make sure it is set to allow enough water to quickly replace the water in the tank during the flush cycle. Since I got this adjusted correctly, no buildup after 2 months. I use 6 minute flush every 4 hours.