How the pH Mini Doser works: The pH Mini Doser automatically doses pH adjuster (up or down depending on your source water) in small doses to your exact pH set points. Once you program the pH set point (e.g. 6.1) and fill the stock tank with pH adjuster, the Mini Doser does the rest. The pH Mini Doser constantly monitors your pH levels, adding pH adjuster only when it is needed and in very small amount