There's a trend afoot to lower the pH using only CO2 gasd by 1.0 pH units to get ~ 25-30ppm.

So if the water is 8.0, then you need to knock the pH down to 7.0.

Your KH is 130ppm or about 7, moderately hard, not too bad.
You could cut it 50/50 and get a KH of about 3-3.5 etc.

Do not concern yourself so much pH.
Use it to determine the CO2 is all.

CO2 and KH are more important than a particular pH.


Regards,
Tom Barr