How to raise your pool’s pH
Updated:
Low pH is corrosive: it eats heater cores, etches plaster, and irritates eyes. Which product you use depends on your alkalinity. If alkalinity is also low, soda ash fixes both. If alkalinity is fine, aeration raises pH for free without touching it.
Step by step
- Test pH and total alkalinity togetherThese two decide the fix. Alkalinity is the buffer holding pH steady, so a pool that keeps falling low almost always has low TA underneath.
- If alkalinity is also low, use soda ashSoda ash (sodium carbonate) raises pH strongly and alkalinity moderately, which is exactly right when both are down. Use the calculator for the amount.
- If alkalinity is fine, just aerateAeration drives off dissolved CO₂, which raises pH and leaves alkalinity alone. Point returns upward, run a fountain or spa jets, or run a waterfall. It costs nothing but time.
- Pre-dissolve and add slowlyDissolve soda ash in a bucket of water and pour it around the pool with the pump running. Adding too much at once clouds the water and can leave a scale deposit.
- Re-test after a full turnoverWait several hours, circulate, then re-test before adding more. pH moves in a curve, not a line, so chasing it with back-to-back doses overshoots.
FAQ
Baking soda or soda ash to raise pH?
Soda ash (sodium carbonate) for pH — it moves pH a lot and alkalinity a little. Baking soda (sodium bicarbonate) is the opposite: it raises alkalinity with only a small pH nudge. Pick based on which reading is actually low.
Can I use borax to raise pH?
Yes. Borax raises pH with less effect on alkalinity than soda ash, which makes it useful when pH is low but TA is already at the top of range.
Why does my pool pH keep dropping?
Usually low alkalinity, so there is nothing buffering it. Chronic acid rain, heavy rainfall, or trichlor tablets (which are acidic) also pull pH down. Fix alkalinity first and pH stops wandering.
Is low pH dangerous?
For your pool, yes — below about 7.0 the water is aggressive enough to corrode metal and etch plaster surfaces. Swimmers mostly notice stinging eyes. Do not swim below 7.0 or above 8.0.
Related
Stop guessing. Get the exact fix
DoseMyPool turns your test numbers into the precise doses and the safe order to add them. Free on the App Store.
Coming soon to the App Store