This is an example of "Hardness" calculations going wrong. It's all grey 'cos it's viewing the "Foetid Mire" area (or "under-the-hood", the bit best stayed out of).
It is from the "Battle, Kent" water analysis (but not SE Water's one) loaded into the "Defuddler" as a "default". This analysis does actually balance (chemically): Notice the two values on the right-hand side? 170.1ppm against 171.53ppm; that's balanced as near as damn it (it stops stuff higher up the spreadsheet in the more visible area turning "red"). But the values for Permanent Hardness and Temporary Hardness are red and faded. You can just about see why: "Permanent" is negative, and "Temporary" is greater than the reported Total Hardness. (It really doesn't make sense, don't waste your time trying to check!).
I haven't modified the values, only part obscured them as they play no further part in adjusting this water. Other "full-blown" water calculators do similar, but don't make the deception so obvious: For example, "Bru'n Water" doesn't allow Temporary Hardness to ever exceed Total Hardness, and therefore Permanent Hardness gets no lower than "zero". Dodgy! But they have no impact on further calculations ... and who notices?
I guess this occurs because some alkalinity isn't associated with "Hardness" elements like Calcium. Say it's from
Sodium Carbonate? Still creates "alkalinity", but creates zero "hardness". It can occur naturally in rare cases. It can also occur in "ion exchange water softeners" (not at source in UK).
The other thing worth pointing out in this view is "Magnesium": Notice the value given it down here is a whopping 20.5ppm? The report only gave it 4.99. But the first figure is "as CaCO3". So, ask yourself, "what has Magnesium got to do with CaCO3?". And why is it added to "Total Hardness"?
I do start this section with: "
Down here all is not what it seems!".