Adjusting for ph

So my water is high in sulphates , so my next beer I'm going to do with spring water. I picked up some ph strips. So as I understand it, I test the ph of my mash after I get rid of any dough balls. Is there a guide out there as to what to add if the ph is high or low, and how much?
Hopefully this will help get rid of this bitterness I'm getting that shouldn't be there.
Thanks

Start by reading the sticky:
https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/

Basically, you're unlikely to have a pH that's too low, so additives to reduce pH are generally what you want. Since you can get sulfate from your tap water, you'll want calcium chloride. That alone may put some mashes in the happy range, others may need acid or acidulated malt. Verifying that will be difficult at best with pH strips.

Acidulated malt, lactic acid, and phosphoric acid are generally used to lower mash pH. Any acid will work, but I'd probably not use acetic. Some people will use citric in a pinch without ill effects.

To raise pH, slaked lime is the most effective, but unless you're got a lot of very dark roasted grain you probably won't have to raise the pH.

Something to keep in mind too, with the pH strips, is they consistently measure incorrectly. They'll generally tell you the pH is 0.2-0.3 to low, so don't freak out and add a bunch of lime if they say the pH of the mash is 4.9.