I have high pH in my all of my hydro systems but one is and stays very high (8.3 while the others are ~6.8-7.4). I am getting a pH of over 8 in one system. I am getting good growth and yields even though the pH is high.

I have used vinegar and am currently trying citric acid. I find I need about 4 teaspoons of dry citric acid to lower the pH of 20gals from 8.3 - 6.3. Does that seem like a lot?

I do have hard water and which has a pH of 8.3 so I probably have some sort of a buffer in the water (well water). I use to use only RO water but I still had a high pH. What are some simple fixes to this problem?

Should I continue to add citric acid or vinegar in these high amounts? OR do I need something stronger like Phosphoric acid and where can I buy it?

TIA,

Chris