What Does Baking Soda Do to My Pool?
Reviewed by a Certified Pool Technician (CPT)
The Short Answer
Baking soda (sodium bicarbonate) raises your pool's total alkalinity, which helps stabilize pH and improves chlorine effectiveness. It's commonly used when alkalinity falls below 80 ppm the low end of the range recommended by the Pool & Hot Tub Alliance (PHTA) for most residential pools. Always test your water before adding any chemicals, add baking soda gradually with the pump running, and retest after full circulation to avoid overcorrecting.
If you've ever Googled "how to fix my pool water" and ended up staring at a box of Arm & Hammer wondering if it could actually help, yes, it can. Baking soda is a legitimate, effective pool chemical. It's the same active ingredient found in products sold as "Alkalinity Up" at pool supply stores, and pool owners have been using it for decades to bring low-alkalinity water back into balance.
That said, knowing what it does is only half the picture. Knowing when to use it, how much to add, and what mistakes to avoid is what keeps you from chasing your pool chemistry in circles. This guide covers all of it.
pH and Alkalinity in Swimming Pools
Before getting into baking soda specifically, it helps to understand the relationship between pH and alkalinity because these two measurements are closely linked and often confused.
pH measures how acidic or basic your water is on a scale of 0–14. The ideal range for pool water is 7.2–7.6. Below 7.2 and the water becomes corrosive; above 7.8 and chlorine loses effectiveness rapidly.
Total alkalinity measures the water's ability to resist changes in pH its "buffering capacity." When alkalinity is low, pH becomes unstable and can swing up and down unpredictably, a condition sometimes called pH bounce. When alkalinity is in range, pH stays stable and much easier to manage.
Per PHTA/APSP industry guidelines, the recommended total alkalinity range for most residential pools is 80–120 ppm. Saltwater pools and pools with vinyl liners are often kept toward the lower end of that range (80–100 ppm); plaster pools can tolerate the higher end.
The practical takeaway: fix your alkalinity first, then address pH. A pH reading is unreliable when alkalinity is out of range, so checking them in the wrong order leads to unnecessary chemical adjustments.
When Should You Add Baking Soda to Your Pool?
Add baking soda when your total alkalinity tests below 80 ppm.
Symptoms of low alkalinity include:
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pH that won't hold steady, it tests fine one day and is off the next
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Corrosive water that irritates eyes and skin
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Etching or pitting on plaster surfaces
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Faster-than-expected chlorine depletion
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Metal equipment and fittings showing signs of corrosion
What baking soda does not do is significantly raise pH on its own. It primarily targets total alkalinity. If your alkalinity is in range but your pH is low, the right product is soda ash (sodium carbonate), not baking soda. Using baking soda to fix a low-pH-only problem will push alkalinity too high without meaningfully correcting the pH.
A quick test with a good test kit or test strips will tell you exactly which problem you're dealing with. Never add chemicals without testing first.
How Much Baking Soda Does Your Pool Need?
The standard dosing rate, used by pool technicians and consistent with most product label guidance, is:
1.5 lbs of baking soda per 10,000 gallons raises total alkalinity by approximately 10 ppm.
Use the table below to find your starting dose based on your pool size and how far your alkalinity needs to come up.
Baking Soda Dosing Chart
Note: These are starting estimates. Actual results vary based on current water chemistry, water temperature, and product purity. Always test before adding and retest after full circulation before adding more.
Important: If your alkalinity is significantly low, say, 40 ppm when it should be 80–100 ppm, don't try to correct the full deficit in one treatment. Add enough to raise alkalinity by 20–30 ppm, let the water circulate and equalize for several hours, retest, and add more if needed. Gradual correction gives you more control and prevents overshooting.
Baking Soda vs. Alkalinity Increaser: Is There a Difference?
This is one of the most common questions pool owners ask and the answer is straightforward:
Household baking soda and pool alkalinity increaser are chemically identical. Both are sodium bicarbonate (NaHCO₃). The molecule is the same. The effect on your pool water is the same.
The differences are practical, not chemical:
The main reason to buy an alkalinity increaser marketed for pools isn't chemistry, it's convenience. Pool-grade products come in larger quantities suited to the doses pools actually require, and the packaging includes pool-specific dosing instructions that save you the math. A 50-lb bag of pool alkalinity increaser is more practical for a 20,000-gallon pool than twelve boxes of Arm & Hammer, but if you only need a few pounds for a minor adjustment, the grocery store version works fine.
What baking soda does not replace: soda ash (sodium carbonate), which raises pH more aggressively than alkalinity. These are related but different chemicals, baking soda for alkalinity, soda ash for pH. Don't substitute one for the other.
How to Add Baking Soda to Your Pool: Step by Step
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Test your water first. Use a test kit or strips to confirm total alkalinity is below 80 ppm before adding anything. Record your reading.
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Calculate your dose. Use the chart above or the formula (1.5 lbs per 10,000 gallons per 10 ppm increase needed). If you need a large correction, plan to split it across multiple treatments.
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Run the pump. Make sure your circulation system is running before you add any chemical.
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Add baking soda to the pool. Broadcast it slowly across the surface of the deep end while walking around the pool. Don't dump it all in one spot; this can temporarily cloud the water and cause uneven distribution.
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Let it circulate. Run the pump for at least 6 hours before retesting. Overnight circulation is ideal for large adjustments.
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Retest and adjust. Check alkalinity again after full circulation. If it's still below 80 ppm, calculate a follow-up dose and repeat. Don't skip this step; overcorrecting alkalinity above 120 ppm creates its own problems.
Common Mistakes When Using Baking Soda in a Pool
Adding It Without Testing First
Baking soda raises alkalinity. If your alkalinity is already in range or high adding more pushes it above 120 ppm, which causes its own set of problems: cloudy water, scale formation, and pH that resists adjustment. Test before every chemical addition, no exceptions.
Trying to Fix Everything at Once
If your alkalinity is 50 ppm and your target is 100 ppm, you need a 50 ppm increase. That's a lot of baking soda. Adding it all at once can overshoot and make pH adjustments difficult afterward. Treat in 20–30 ppm increments, retest, and continue as needed.
Confusing Baking Soda with Baking Powder
Baking powder contains baking soda plus cream of tartar and sometimes cornstarch. It is not the same product and should not be used in a pool. Use pure baking soda (sodium bicarbonate) only.
Using Baking Soda to Fix Low pH
Baking soda raises alkalinity. It has a modest effect on pH, but it's not the right tool for a pH-only problem. If your alkalinity is fine but your pH is low, use soda ash (sodium carbonate). If you're unsure which problem you have, test both before adding anything. For a deeper look at how muriatic acid works on the other end of pH adjustment, see our guide on what muriatic acid does for a pool.
Not Waiting Long Enough to Retest
Baking soda needs time to fully dissolve and distribute through the water. Testing 30 minutes after adding a large dose will give you an inaccurate reading. Wait for at least one full circulation cycle, typically 6–8 hours, before making additional adjustments.
How Pool Alkalinity Connects to Your Other Chemistry
Alkalinity doesn't exist in isolation. Getting it right makes everything else easier:
Chlorine effectiveness: Chlorine works most efficiently at a pH of 7.2–7.6. When alkalinity is low and pH bounces around, you get periods of over- and under-chlorination even when you're adding the right amount. Stable alkalinity means more predictable chlorine performance. For a full overview of proper chlorination, see how to properly chlorinate your pool in three easy steps.
Equipment protection: Corrosive, low-alkalinity water attacks metal fittings, pump housings, and heater heat exchangers. Keeping alkalinity in the 80–120 ppm range protects your equipment investment. If you're not sure what else belongs in a proper pool maintenance kit, our essential pool care equipment list is a good starting point.
Swimmer comfort: Low alkalinity means low or unstable pH, which causes eye and skin irritation. A pool that's consistently comfortable to swim in is one where alkalinity is consistently managed.
Vacuuming and surface care: Corrosive water etches plaster and can degrade vinyl liners over time. If you're vacuuming regularly but still noticing surface issues, water chemistry — not cleaning frequency is usually the culprit. See do I need to vacuum my pool every day for context on how chemistry and cleaning interact.
Frequently Asked Questions About Pool Alkalinity
What does baking soda do in a pool?
Baking soda (sodium bicarbonate) raises total alkalinity, which stabilizes pH and improves chlorine effectiveness. It's used when total alkalinity falls below the PHTA-recommended range of 80–120 ppm.
How much baking soda do I add to raise pool alkalinity?
The standard rate is 1.5 lbs per 10,000 gallons to raise alkalinity by approximately 10 ppm. For a 20,000-gallon pool that needs a 20 ppm increase, start with 6 lbs, circulate for 6–8 hours, and retest before adding more.
Is baking soda the same as pool alkalinity increaser?
Yes. Both are sodium bicarbonate (NaHCO₃), chemically identical. Pool alkalinity increaser is packaged and labeled for pool use, often in larger quantities. Household baking soda works the same way.
Can you add too much baking soda to a pool?
Yes. Alkalinity above 120 ppm causes cloudy water, promotes calcium scaling, and makes pH difficult to lower. Always test before adding and increase alkalinity in 20–30 ppm increments rather than correcting a large deficit all at once.
Will baking soda raise my pool's pH?
Baking soda raises alkalinity and has a minor effect on pH. It is not the right product for a pH-only adjustment. If your alkalinity is in range but pH is low, use soda ash (sodium carbonate) instead.
How long after adding baking soda can I swim?
Generally you can swim within a few hours of adding baking soda, once it has fully dissolved and circulated. Retest your water before allowing swimming to confirm chemistry is in the correct range.
How often do I need to add baking soda to my pool?
There's no fixed schedule, it depends on your pool's usage, rainfall, and source water chemistry. Test your water at least weekly during swim season and add baking soda whenever total alkalinity drops below 80 ppm.
What's the difference between baking soda and soda ash for pools?
Baking soda (sodium bicarbonate) primarily raises total alkalinity with a minor effect on pH. Soda ash (sodium carbonate) raises pH more aggressively and also increases alkalinity. Use baking soda for low-alkalinity corrections; use soda ash when pH needs a larger boost.
This article was reviewed by a Certified Pool Technician (CPT). Total alkalinity targets referenced are consistent with PHTA/APSP guidelines for residential pool water chemistry. Always test your water before adding chemicals and follow product label instructions for specific dosing guidance.
