I live in Seattle where the water is quite soft, which is nice because it's straightforward to hit a target water profile through adding brewing salts. I recently used the BrewersFriend.com mash chemistry and brewing water calculator, and chose the "Burton on Trent (historic)" target profile. Getting to this profile requires adding quite a bit of salts, most notably gypsum, in pursuit of high ion levels: Calcium = 270ppm and Sulfate = a whopping 720ppm. Having hit this target, the water calculator reports in the overall summary that the Ca level is Harmful (and advises not to brew at this ion level). Please see attached screenshot. In fact one of the help pages says "Concentrations above these levels are harmful to the beer, and much beyond they become harmful to our health!" If I instead target the profile titled "Burton on Trent (historic and decarbonated)" then at least I am not in the Harmful range on Calcium, but still high on 3 of the 5 main ions. Question: is it truly harmful to humans to target the historic Burton water profile? The following article mentions that a high bicarbonate level balances the negative effect of high calcium, but I want to be sure that neither my beer nor my beer drinkers are going to truly suffer.