I grow in soil, but my well water is 8.0ish right out of the tap.

I was always told to adjust the water, then add nutes. So I add 1 teaspoon of ph down (phosphoric acid) per 5 gallons of water, which puts the ph at 6.8ish. Then I add the nutes.

Since I can't test runoff water with my color-coded test kit, I had gotten one of those cheap soil ph probes, and lowest it ever read was 6.2ish.

However, I have no experience with hydro so my info may not help your situation.