Martin, would you say that harder water has a greater buffering capacity? And that softer water would have a less robust buffering capacity? Or is the relationship between water and buffering capacity related to something other than just relative ion concentrations?
I'm not sure if EZ Water Calc 2.0 factors in the buffering capacity of the water (or if it does, to what extent), but if soft water (defined for the purpose of this thread as my water profile in the screenshot above) has less buffering capacity, it would provide some explanation for my measured results, i.e., my soft water does not offer as much buffering resistance to the acidifying darker malts in darker beers, which is why I need to add more salts (CaCO3 and/or NaHCO3) to hit my mash pH.