Originally Posted by adam01
The water report lists 'Hardness' as 55 (average). This is probably what you are looking
No, he said alkalinity or bicarbonate neither of which is listed. Also he specifically said Bear Gulch which has an average hardness of 170. The 55 number is for the SFPUC district.
You may be confusing "carbonate hardness" with hardness. Carbonate "hardness" is the term Europeans sometimes use to describe alkalinity. In this case it means the part of the hardness which is paired with bicarbonate i.e. the alkalinity (at pH < 8.3). Here, the carbonate hardness, usually called "temporary hardness" in the US, is about 170 with the rest of the 189 being being "permanent hardness" (paired with sulfate and chloride). If there is no chloride or sulfate (or other anion) then alkalinity and hardness are the same.
And yes, I did say 50 last night but that was because, like the big dummy I can sometimes be, I didn't notice that the "as sulfur" check box on my spreadsheet was selected. The total alkalinity for these data would be about 189. I'll go back and correct yesterday's post.