Guide
Pool pH and Alkalinity — What to Fix First
Total alkalinity vs pH in pool water — why TA is the buffer, when to use acid or baking soda, and how to avoid chasing pH daily.
pH is how acidic or basic the water feels right now. Total alkalinity (TA) is the buffer that resists pH change. Fixing pH while TA is wrong is why some pools need acid every other day.
Which one first?
Usually TA, then pH — once sanitizer is under control.
- TA low: pH bounces; add baking soda, circulate, retest.
- TA high: pH often sits high; acid lowers both TA and pH — dose carefully and retest.
- pH high, TA OK: small acid doses (or aeration strategies depending on situation).
- pH low, TA OK: soda ash sparingly; don’t create a new TA problem.
Acid safety (non-negotiable)
- Add acid to water, never water to acid.
- Prefer partial doses and retests over dumping the full demand at once.
- Brush and circulate so you don’t create acidic pockets near surfaces.
Pooldex caps acid recommendations to roughly one-third of demand with “retest between” guidance for exactly this reason.
Why pH drifts up
Aeration, outgassing of CO₂, some chlorine products, and heavy feature use push pH up. That’s normal. A stable TA band makes the drift manageable instead of constant.
Log the pair together
When you only save pH, you can’t tell whether yesterday’s acid worked on TA, pH, or both. Enter both when you test both. Pair with how to balance pool water for the full order of operations.