I am not sure what hardness setting is required. I tested the water and came up with the third reading from the left which said 7ppm, is this what I set the water sofner at is 7. It comes preset at 25. There is 7 colors on the strip the 3 matched my water hardness, but unclear what to set at. Other number close to the 7 or above the 7 was 125, which the softner settings do not go that high..