Raising PH is logarithmic so someone with a PH of 6.0 that uses it to raise the PH to 6.5 would use a different amount than someone raising the PH of 7.0 to PH 7.5. So you just have to experiment with your own water chemistry. Although it's easiest not to mess with PH parameters until you know how to manipulate your buffering capacity (KH value).