Baking soda (sodium bicarbonate) raises a pool's total alkalinity, not its pH. Adding about 1.5 lb per 10,000 gallons raises alkalinity roughly 10 ppm, which steadies pH and stops it bouncing. To raise pH itself, use soda ash instead.
What Baking Soda Actually Does
Baking soda — sodium bicarbonate — is the same product sold in pool stores as "alkalinity increaser," just in a smaller box. Its real job is to raise total alkalinity (TA), not pH. That distinction is the whole point of this guide, because most people reach for baking soda hoping to fix pH and end up confused when the pH barely moves.
Total alkalinity is your water's buffer — its resistance to sudden pH swings. When TA is too low (under about 80 ppm), pH becomes unstable and "bounces": a little acid or a little chlorine sends it crashing or climbing. Raising TA into the 80–120 ppm range gives pH something to hold onto, so the whole pool becomes easier to balance.
In short, baking soda does three things in a pool:
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Raises total alkalinity — about 1.5 lb per 10,000 gallons gains roughly 10 ppm.
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Steadies pH — TA of 80–120 ppm is the buffer that stops pH bouncing after acid or chlorine.
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Barely moves pH itself — if pH is what's low, that job belongs to soda ash.
The one thing to remember
Baking soda raises alkalinity with only a small nudge to pH. If your pH itself is low and you want to raise it, that's a job for soda ash (or aeration), not baking soda.
Baking Soda vs Soda Ash
They sound similar and both come as white powder, but they do different jobs — mixing them up is the single most common alkalinity mistake.
| Baking Soda | Soda Ash | |
|---|---|---|
| Chemical | Sodium bicarbonate | Sodium carbonate |
| Raises mainly | Alkalinity (TA) | pH |
| Effect on the other | Small pH rise | Some TA rise |
| Use when | TA low, pH okay | pH low |
Quick rule: low alkalinity → baking soda. Low pH → soda ash. If both are low, start with baking soda to fix TA, then re-test — often pH settles into range on its own once the buffer is restored. If it is really pH you need to raise, the pH calculator doses soda ash for you. For dosing, overdose risk, and a full side-by-side, see the baking soda vs soda ash comparison.
How Much to Add
The working number to remember: about 1.5 lb of baking soda per 10,000 gallons raises total alkalinity by roughly 10 ppm, with only a minimal effect on pH. Scale that to your pool size and to how far below range you are.
| Pool size | Raise TA +10 ppm | Raise TA +20 ppm |
|---|---|---|
| 10,000 gal | ~1.5 lb | ~3 lb |
| 15,000 gal | ~2.25 lb | ~4.5 lb |
| 20,000 gal | ~3 lb | ~6 lb |
Don't try to close a big gap in one shot. If a dose works out at more than about 2.5 lb, split it into doses six to eight hours apart, running the pump between each, and re-test before the next. Overshooting TA is annoying to reverse — it takes acid, which then drags pH down too.
Get the Exact Amount
Enter your pool volume and current vs target alkalinity — the calculator gives you the exact pounds of baking soda, no scaling math.
Alkalinity CalculatorHow to Add It
- 1
Test TA and pH first, and measure your pool volume, so you know the real gap. Strips are fine for a ballpark; a drop kit is more accurate for alkalinity.
- 2
Run the pump so the water is circulating. Baking soda dissolves easily, so you can broadcast it slowly across the deep end, or pre-dissolve it in a bucket of pool water and pour that in.
- 3
Let it circulate for at least 6 hours (ideally overnight) before re-testing. Adding more before it's fully mixed is how people overshoot.
- 4
Re-test and repeat if needed. You can usually swim within an hour of a normal dose once it's dispersed — baking soda is gentle — but follow the product label if you're using a branded increaser.
Common Mistakes
Using it to raise pH
Baking soda barely moves pH. If your pH is genuinely low, you'll dump in pounds of it, over-raise TA, and still have low pH. Use soda ash for pH.
Dumping the whole amount at once
Big single doses overshoot and cloud the water briefly. Add in stages, circulate, re-test.
Expecting it to clear cloudy water
Baking soda isn't a clarifier. Cloudiness is a chemistry, filtration, or mechanical problem — see the cloudy water guide, not the baking soda box.