Calculate how much muriatic acid to add to lower your pool's pH or total alkalinity.
Always pre-dilute in a bucket of pool water before adding. Pour acid into water, never water into acid. Wear eye protection and gloves. Add near a return jet with the pump running, never near the skimmer. Never mix with chlorine or other chemicals.
Both use the same chemical (muriatic acid), but the goal determines how much you add and what you do next.
Lowering pH is the most common use. If your pH is above 7.8, acid brings it back into the 7.4–7.6 target range. Adding acid also drops TA slightly, which is usually fine unless your TA is already low.
Lowering total alkalinity uses a larger acid dose to deliberately reduce TA. Because this also drops pH sharply, you then aerate the water to drive CO₂ off and raise pH back to 7.4–7.6 — without raising TA. This is the correct sequence when TA is high and causing persistent pH drift upward.
If your pH keeps drifting up no matter how much acid you add, high total alkalinity is almost always the cause. Bring TA to 60–80 ppm first — then pH stabilizes and requires far less maintenance acid over the season.
For pH: The acid dose is proportional to the pH drop and the current alkalinity. Higher TA means more buffering capacity, so more acid is required for the same pH change.
For TA: The relationship is direct — each ppm of TA reduction in a given volume requires a fixed amount of acid.
PoolChem Tracker calculates your muriatic acid dose automatically from your logged readings — no calculator required. It also tracks how pH and TA trend after each treatment.
