Are you keeping and breeding rare fish? Because if you aren't, then you don't need to fret over the acidity or alkalinity of your tap water. The vast majority of aquarium fish will adapt to the vast majority of public water supplies. Our fish will thrive in a pH between 6 - 8.5 as long as the level is stable.
Just treat the tap water and remove the ammonia, chlorine and chloramine and don't get creative in an attempt to change the water pH and your fish will adapt. They've been doing this since the hobby started.
Just a couple of thougths.
"Fear not my child, just change the tank water."