PU does add calcium salts to their water. Some anecdotal findings I recall from AJ Delange indicate that around 30 ppm chloride and 20 ppm calcium produce a more flavorful beer. I've done several light lagers with around 20 to 30 ppm calcium in the overall wort and they fermented and cleared well and they tasted very good. Brewing with much lower mineral content can leave the beer flavor bland. You need some...not much though.Good info. I need to try brew one again.