#### MajorTom

##### Well-Known Member

- Joined
- Nov 19, 2008

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Looking at Palmer's spreadsheet I see that the Effective Hardness comes from Ca/1.4 + Mg/1.7. Where do these numbers(1.4 and 1.7) come from and what is the unit measure for Effective Hardness? I assume it is ppm, but I don't understand why the Ca and Mg are reduced by 1.4 and 1.7.

Any water geniuses out there care to help me?