It's not copious amounts IMO.
It hugely interesting. As you know we in the UK have such diversity, from the chalk laden water of the south, the sulphate water of Burton to the super soft water of the frozen north and everything in between. The pH of my tap water is 6.5, a kick in the bum away from RO water, i just stare at my water and it acidify, on the other hand brewers elsewhere might have to try all sorts of boiling and buckets of acid to get it to a reasonable level. Murphy's advocate almost 200ppm of calcium, that is huge for me to even reach, I'd have to add 12g of calcium sulphate and 12g of calcium chloride to get close to those kind of levels. thats pretty big for someone that is used to using maybe 1.2 grams of each for mash and a similar amount for sparge. For someone else they may only need to add relatively few additions to reach those kind of levels. The interesting thing though is why are Murphys advocating these levels?
Beer is an expression of the human spirit. . . we use technical sciences as a tool to create it but its essence is and always will be a form of art - Handbook of brewing, chapter 2, page 55