It depends on your tap water...sounds like yours isn't too out of whack but it is hard to speculate; fwiw, my tap water (that doesn't appear to have chromium, based on local water quality reports), is ~8+ I believe, and I air-out ~24-48hrs for chlorine reasons, but I've never owned a PH tester and have no idea what the soil PH is; I currently just use roughly the same amount of down from a dropper per 2 gallons at a time to roughly get in the ~mid 6s PH for the water going in (and re-test by color maybe once or twice a grow in case my tap PH changes for some reason)
I'm also growing in SIPs these days which only hold maybe ~3-3.5 gallons of soil, and I think a straight 5-7 gallon soil pot (if watered effectively, which is a huge if) would be more forgiving