NPK the big 3, then sulphur/calcium those are the 5 macro nutrients. Then you have all the micro nutrients.
Every nutrient has a very specific "optimal" pH for uptake, some uptake best at 5 some at 7.5 like nitrogen, but if we make the ph 7.5 it will cut off other nutrient all together.
We use 6.0 -6.5 as a general range because everything uptakes "reasonably" well within it.
Once you break things down to an atomic level once a atom is stable it emits either a positive or negative charge, every nutrient has a very particular magnetic signature or magnetic charge, essentially dictating which way the atoms rotate as they spin.
As something becomes more "acidic" the atoms start to become more excited, this causes friction, like when you run your hands together, gives acid it's ability to dissolve.
0ppm h2o at room temperature = 7.0 pH
0ppm h2o at rapid boil = 6.2 pH
If your adding shit to your grow that alters the ph then yes it's important.
