pH is the single most important number in your pool. It controls how well your chlorine sanitizes, how comfortable the water feels, and whether your equipment and pool surface get eaten alive over time. Miss this one and nothing else you do matters.
The target range for pool pH is 7.4 – 7.6. That's tight on purpose — it's the sweet spot where chlorine is most active, swimmer comfort is highest, and neither scale nor corrosion gets a foothold.
What pH actually measures
pH is a logarithmic scale from 0 (very acidic) to 14 (very basic), with 7 being neutral. Every 1-point change is a 10x change in acidity. That's why a pool at 7.2 is twice as acidic as one at 7.5 — the numbers look close, but the chemistry is meaningfully different.
Pool water naturally wants to rise in pH over time because chlorine tablets are acidic (pulling pH down as they dissolve), but aeration, heat, and CO₂ off-gassing push it back up. In Florida's high-temperature environment, pH drift upward is the norm.
How to lower pool pH
Use muriatic acid (31.45%) or dry acid (sodium bisulfate). Liquid muriatic is cheaper per dose but requires careful handling. Dry acid is safer for homeowners but costs more per ppm.
Dosing rule of thumb (10,000-gallon pool):
- Lower pH by 0.2 → 8 oz muriatic acid or 12 oz dry acid
- Always add to a return jet with the pump running
- Wait 4 hours, retest, and dose again if needed — never dose twice in a row
The #1 mistake: dumping a full quart of acid to “really fix it.” You'll crash the pH below 7.0, kill your alkalinity, and spend the next three days chasing the pool back into range.
How to raise pool pH
Use soda ash (sodium carbonate) to raise pH without disturbing alkalinity much. Use sodium bicarbonate (baking soda) if you need to raise both pH and alkalinity together.
Dosing rule of thumb (10,000-gallon pool):
- Raise pH by 0.2 → 6 oz soda ash
- Pre-dissolve in a bucket of pool water before pouring in
- Broadcast into the deep end with pump running
Why your pH keeps drifting
If you're constantly adding acid, suspect one of these:
- Total alkalinity too high — TA buffers pH upward. Get TA into 80–100 ppm.
- Aggressive aeration — waterfalls, spa jets, and high-flow returns outgas CO₂ and push pH up.
- Salt chlorine generator running hot — SCGs produce high-pH chlorine at the cell.
- Fresh plaster — new plaster leaches calcium hydroxide for up to a year.
Testing pH correctly
Don't trust cheap test strips for pH — they're notoriously unreliable. Use a liquid reagent kit (phenol red) or a calibrated digital meter. Test at the same time of day for consistency; morning readings before sun exposure are ideal.
When to call a pro
If your pH refuses to stay in range despite correcting alkalinity, or if you're going through a gallon of acid per week, something upstream is wrong — usually a misbehaving salt cell, a fresh plaster finish, or out-of-range CYA masking the real issue. Our team can diagnose in one visit.