The Baking Soda
Pool Calculator
Low alkalinity makes pH bounce all over the place. Enter your pool volume and test results to get the exact pounds of baking soda to add — no guesswork.
Why Alkalinity Matters (and What Baking Soda Actually Does)
Total alkalinity (TA) is your water's pH shock absorber. When TA drops below about 80 ppm, pH swings wildly with every rainstorm and chlorine dose — that's the classic "my pH won't stay put" complaint. Baking soda is pure sodium bicarbonate: it raises alkalinity directly while only nudging pH slightly, which makes it the right tool when TA is low.
- Test first: Get a reliable TA reading with a drop test kit or fresh strips. Aim for 80–120 ppm (90–100 is the sweet spot for most chlorine pools).
- Know your volume: The dose scales directly with gallons. Not sure? Use the free volume calculator.
- Add, circulate, retest: Broadcast the powder across the deep end with the pump running. Retest after 6+ hours before adding more.
Baking Soda Dosing Chart
Pounds of baking soda needed by pool size and how far you're raising total alkalinity:
| Raise TA By | 10k gal | 15k gal | 20k gal | 25k gal | 30k gal |
|---|---|---|---|---|---|
| +10 ppm | 1.4 lbs | 2.1 lbs | 2.8 lbs | 3.5 lbs | 4.2 lbs |
| +20 ppm | 2.8 lbs | 4.2 lbs | 5.6 lbs | 7.0 lbs | 8.4 lbs |
| +30 ppm | 4.2 lbs | 6.3 lbs | 8.4 lbs | 10.5 lbs | 12.6 lbs |
| +40 ppm | 5.6 lbs | 8.4 lbs | 11.2 lbs | 14.0 lbs | 16.8 lbs |
| +50 ppm | 7.0 lbs | 10.5 lbs | 14.0 lbs | 17.5 lbs | 21.0 lbs |
Raises of more than ~20 ppm should be split into multiple doses with a retest in between. Odd pool size? The calculator above handles any volume.
Baking Soda vs. Soda Ash: Don't Mix Them Up
These two white powders get confused constantly, and adding the wrong one makes your water chemistry worse:
Baking Soda (Sodium Bicarbonate)
Raises total alkalinity a lot, pH only a little. Use it when TA is under 80 ppm and pH is roughly okay (7.2+). This is also exactly what pool stores sell as "Alkalinity Increaser" — same chemical, different label, usually a higher price.
Soda Ash (Sodium Carbonate)
Raises pH strongly (and alkalinity some). Use soda ash (pH Up) when pH has crashed below 7.2. If you use soda ash to fix low alkalinity you'll overshoot pH badly. Dose it with the chemical dosage calculator.
Frequently Asked Questions
How much baking soda does it take to raise alkalinity 10 ppm?
About 1.4 lbs per 10,000 gallons. A typical 15,000-gallon pool needs roughly 2.1 lbs for every 10 ppm of increase — so going from 50 to 90 ppm takes about 8.4 lbs.
Is pool "alkalinity increaser" the same as baking soda?
Yes — it's sodium bicarbonate, chemically identical to grocery-store baking soda. Buying plain baking soda in bulk bags is the exact same fix at a fraction of the price. Check the label: if it says "sodium bicarbonate 100%," it's the same thing.
Will baking soda raise my pool's pH?
Only slightly. That's the point of using it: big alkalinity lift, small pH nudge. If your pH is badly low (under 7.2) and alkalinity is fine, you want soda ash instead.
How long after adding baking soda can I swim?
Once it's dissolved and circulated — typically about an hour with the pump running — it's swim-safe. Wait at least 6 hours of circulation before retesting and re-dosing.
Can I add too much baking soda to a pool?
Yes. Above ~120 ppm TA, pH constantly drifts up and the water leans toward cloudiness and scale. Overshooting is a pain to reverse (it takes acid and time), so raise in ~20 ppm steps and retest between doses.
Next Steps: Balance the Rest
Alkalinity is the foundation — once it's in range, dial in chlorine, pH, and stabilizer.