pH indicates the acidity or alkalinity of a substance. The scale runs from 0 to 14. PH value 7 is neutral, lower than 7 is acidic, and higher than 7 is alkaline. Tap water is usually in the range of 7. With electrolysis, pH goes up as ORP goes down. You can regulate the pH directly with the level setting of the machine, or indirectly by changing the water flow. If you slow down the water flow, you are intensifying the alkalinity, because the water has more time to go through the electrolysis stage