I use my softened tap water which doesn't test high for sodium and gypsum in varying doses and baking soda for dark beer. I only use brun water for a style I haven't brewed yet and don't bother filling out the spreadsheet each time. You don't want to know how I measure . To me its a ballpark thing and I make good beer that way. Others get way into it and enjoy that aspect of it and make good beer too. That's a nice thing about home brewing, you can do it your own way. My opinion though is that getting the minerals and ph in the right range improves beer but right now its fetishized by a lot of home brewers. I think the fact that its talked about so much and seen as something that needs to be done and people are getting milligram scales and adjusting boil ph and post fermentation ph etc. Is making for a strong placebo effect. If you fill out a spreadsheet, measure four salts to the milligram, calibrate a ph meter, check ph, freak out because its off a little, measure acid, measure ph again etc. Then you will really, really want to taste the difference. And you will, whether its there or not. And that's fine.
If this forum had a motto it would not be dwrhahb, it would be ysbwmayph. (You Should Be Worrying More About Your PH)