Thanks Rice Guy,
I did read that to go slow. I decided to do a trial to see which one I could get better results, each batch was 3 gallons. Batch 1 I added 7.5 gr of calcium carbonate, pH was 2.82, now is 2.88, Batch 2 added 7.5 gr of potassium bicarbonate, pH was 2.83, now is 2.85. Batch 3 I...