pH is UP; Alkalinity is UP

When my pH is down, the alkalinity is either also down, or in the normal range. If I raise the pH to a normal level, the alkalinity either drops further down or down below the normal range. If I then raise the alkalinity back up into the normal range, the pH rises above the normal range, and I start the cycle all over again, only in reverse, lowering the pH back into the normal range, resulting in the alkalinity dropping below the normal range. I use NaBicarb to raise alkalinity, and either muriatic acid or NaBisulfite to lower the pH. I have tried various combinations, doesn’t seem to matter if I make the changes very slowly or quickly, never make more than one change in 24 hours. How can I break this roller coaster cycle? Useful info: 30,000 gal inground gunnite, DE filter, pump running 24/7, water is crystal clear and chlorine levels have always been easy to maintain in normal levels. I have a SpinTouch device to do colorimetric testing daily.

Don’t worry about the PH untill you get the alkalinity correct. Then adjust the PH, otherwise you are just running in circles.

If the PH is high I would use bisulfate at about 1 pound at a time and after a couple of hours recheck PH. But always get the alkalinity first.

I have a 30K gallon pool as well. I use a Taylor test kit which I’ve had for over 30 years. Good luck!