Acid balancing soft tap water for optimal pH?

Hi, I've been tinkering with water chemistry since I got my ZP6, which brought out slight muddiness in my light roasts that had been masked by my Wilfa Uniform. I use unfiltered Nordic tap water, which is very soft to start with (~3-4 °dH), but slightly on the alkaline side of things with pH of 8-8,5. Also I believe it could use a bit more magnesium (only 1,3mg/l) but generally nice for something straight from tap.

So before reaching for epsom salts or dedicated mineral blends, I decided to see what I could do with the citric acid I had around from some mixology experiments. So what I did, was that I boiled a liter of water and added a tiny amount, like a few dozen crystals of citric acid and measured the pH with a test kit to be somewhere around 6.5-7.0. Still tasted neutral but maybe a touch softer, rounder than untreated.

This actually made a difference with the light washed Rwanda Shyira I was testing with. It was juicy to start with, but the acid balanced water made it more transparent and brought out sugarcane-like sweetness on top of the citrus acidity I had already got before. Next I probably need to see what added magnesium can do.

The recipe was my usual:

15g to 240g with ceramic v60, standard white hario paper

ZP6 at 4.0

Double bloom 30 sec apart with 30+30g

Three almost back to back pours of 60g, 15 seconds apart to 240g total

Has anyone else tried something similar? What kind of results have you got? Something that should be taken into account while messing with the pH?