I don't have a pH meter, so I can't check. I just trust whichever calculator I use (usually the advanced brewers friend calculator) that it will be right.
I actually read this article, must have forgotten. Huge Brulosophy fan.
Brewing an American stout on Friday and I used the Ez water calculator, advanced Brewers Friend water calculator and Bru'n'water and all three gave me a different mash pH.
Ez water: 5.57
Brewers Friend: 5.59
Bru'n'water: 5.22
This is without any mineral additions and using RO water...