I used to use acid in my tap water for sparge water to get the pH down to 6. I have since gone to 90% distilled and 10% tap with no acid for sparging and the final runnings pH is always well under 5.8 as long as my mash pH was good. At first I used an eye-dropper (from Walgreens) to add the acid and then went with a burette for more accuracy.
FYI, 17 drops from a Walgreens eye dropper is about 1 mL, measured with the burette.
Fermenting: Sterling IPA, Barrel Fermented Dreg Lambic, Brett Trois Helles, Carrot Blossom Cedar Mead
Drinking: Brown IPA, LabHands, RIS, Dusseldorf Altbier v5, Oktoberfest v5, Dopplebock v2, Cider, Rye Berliner Weisse, Sauerkraut Fermented Gose, Lambic, Brett Trois IPA, Brett Blonde, Kriek, Saison, Sour Blonde, RIS
Barrel aged: RIS, Rye Barleywine, Tripel, Wee-Heavy