Managing water chemistry in a swimming pool is a crucial task that ensures the health and safety of swimmers while preserving the pool structure and equipment. While many chemicals are used to maintain balance, baking soda — or more scientifically, sodium bicarbonate — plays a unique and important role in stabilizing your pool’s pH and alkalinity. If you own or manage a 20,000-gallon pool, knowing how much baking soda to use is essential for optimal water care. In this guide, we’ll explore the exact amount of baking soda needed, why it matters, and how to apply it effectively.
Understanding the Role of Baking Soda in Pool Maintenance
Before determining the right dosage, it’s important to understand the function of baking soda in a pool environment. Baking soda is primarily used to raise the total alkalinity (TA) of the water. Alkalinity acts as a buffer for pH levels, preventing sudden and harmful swings in acidity or basicity.
When your pool water’s pH is unstable, it can lead to a host of problems:
- Eye and skin irritation for swimmers
- Corrosion of metal components like ladders and pool heaters
- Damage to pool liners and surfaces
- Inefficiency of chlorine as a disinfectant
In contrast, properly maintained alkalinity will ensure that your pool remains comfortable, clean, and easy to manage from a chemical standpoint.
Total Alkalinity vs. pH
It’s important not to confuse total alkalinity with pH. While pH measures how acidic or basic your water is, total alkalinity refers to the water’s capacity to neutralize acids. Alkalinity essentially acts as the “shock absorber” of your pool’s chemistry.
The ideal range for total alkalinity is between 80 to 120 parts per million (ppm) for chlorine pools, and slightly higher — 100 to 150 ppm — for saltwater pools due to their unique chemistry.
How Much Baking Soda to Add Per 20,000 Gallons
To raise the alkalinity in a 20,000-gallon pool, you’ll typically use around 1.5 pounds of baking soda to increase total alkalinity by 10 ppm. However, the exact amount depends on your current TA level and your target range.
Here’s a general rule of thumb:
One pound of baking soda raises the total alkalinity by approximately 10 ppm in 10,000 gallons of water.
So for a 20,000-gallon pool, you would need:
| Desired TA Increase (ppm) | Baking Soda Needed (pounds) |
|---|---|
| 10 ppm | 2 pounds |
| 20 ppm | 4 pounds |
| 30 ppm | 6 pounds |
This calculation allows you to tailor the dosage depending on your specific pool’s test results.
Testing Your Pool Water Before Adding Baking Soda
To determine exactly how much baking soda your pool needs, you must first conduct a water test. There are several reliable tools available for this, including:
- Test strips
- Liquid reagent kits (drop tests)
- Digital testing devices
Always test for total alkalinity before adding any chemicals. If your TA reading is already within the ideal range, you may not need to add baking soda at all. Adding too much can lead to high alkalinity, which causes its own set of issues, such as:
- Cloudy, hazy water
- Scaling on pool surfaces
- Reduced chlorine effectiveness
Therefore, testing is not just a suggestion — it’s a requirement.
Step-by-Step Guide to Adding Baking Soda to Your Pool
If you’ve tested the water and decided your total alkalinity is low, follow this step-by-step process to safely and effectively add baking soda:
Step 1: Test the Water
Using your preferred test method, determine the current TA level. Note this number before proceeding.
Step 2: Determine the Target TA Value
If the TA is low (e.g., 60 ppm), determine the amount you need to raise it (e.g., 20 ppm to reach 80 ppm).
Step 3: Calculate How Much Baking Soda to Use
Using the standard formula:
10 ppm increase = 1 pound per 10,000 gallons
For a 20,000-gallon pool, this becomes:
20,000 gallons = 2 pounds per 10 ppm increase
Multiply that number by the desired ppm increase to get the total.
So:
- 10 ppm increase = 2 pounds
- 20 ppm increase = 4 pounds
- 30 ppm increase = 6 pounds
Step 4: Pre-Dissolve the Baking Soda (Optional but Recommended)
Although you can broadcast baking soda over the surface, it’s generally more effective to pre-dissolve it in a bucket of water before pouring it into the pool. This prevents clumping and improves even distribution.
Here’s how:
- Fill a 5-gallon bucket with water from the pool
- Add the calculated baking soda to the bucket
- Stir until fully dissolved
- Pour the solution slowly into the deep end of the pool while the pump is running
Step 5: Circulate the Water for Even Distribution
Run the pump for 6 to 8 hours to ensure the baking soda is evenly distributed throughout the pool.
Step 6: Retest After 24 Hours
It may take 12 to 24 hours for the full effect to show. Retesting after a day ensures accurate results. If alkalinity is still below target, the process can be repeated.
Common Baking Soda Mistakes and How to Avoid Them
Even something as simple as adding baking soda can go wrong if not done properly. Let’s look at some common mistakes pool owners make:
Mistake #1: Adding Too Much Baking Soda at Once
Adding a large amount of baking soda at once can spike your alkalinity and result in cloudy water. Always add in small increments and allow 24 hours for the full chemical change before re-testing.
Mistake #2: Neglecting to Test pH After Alkalinity Adjustment
Remember, alkalinity is a buffer for pH. If you raise the total alkalinity too high, your pH can go up as well, resulting in scaling and water imbalance. Always recheck the pH after TA adjustments.
Mistake #3: Not Considering Pool Type
Some pools — especially saltwater pools — require slightly higher alkalinity levels. Failing to adjust for this can result in chemical inefficiencies. Always check the recommended TA range for your specific pool type.
Mistake #4: Using Baking Powder Instead of Baking Soda
This mistake can be costly and dangerous. Baking powder is a very different substance and will not perform the same function as baking soda. Always ensure you’re using pure sodium bicarbonate for your pool.
Why Using the Right Baking Soda Matters
Not all baking soda is created equal. When selecting a product for your pool, always use pure sodium bicarbonate labeled for swimming pool use, if possible. Some brands may contain additives that are not suitable for pool environments.
Here’s what to look for:
Label Indicators:
- Labeled as “Pool Grade Sodium Bicarbonate”
- Clear listing of “Sodium Bicarbonate” as the sole ingredient
- Sold at pool supply stores or by reputable chemical brands like Clorox, Leslie’s, or AquaChek
While food-grade baking soda from the grocery store can technically be used, it may contain anti-caking agents or perfumes that aren’t ideal for pool use. In general, stick to pool-grade or spa-grade sodium bicarbonate for safety and effectiveness.
Brand Comparison
| Product | Type | Purity Level | Recommended for Pool Use? |
|---|---|---|---|
| Arm & Hammer Pure Baking Soda | Food Grade | 99%+ Pure | Only for emergency use |
| Leslie’s Alkalinity Increaser | Pure Sodium Bicarbonate | 100% Pure | ✅ Yes |
| Clorox Pool & Spa Alkalinity Increaser | Pure | High Purity | ✅ Yes |
When Not to Use Baking Soda in Your Pool
While baking soda is a useful tool in your pool maintenance kit, there are times when it should not be used. You should avoid using baking soda when:
- Your alkalinity is **already at or above** the recommended level (above 120 ppm for chlorine pools)
- Your pool water has already developed **scaling or cloudiness**, which could indicate other chemical imbalances
- If you’re trying to **raise pH independently**, as baking soda can raise both pH and TA and may not be appropriate in all cases
In those instances, other pool chemicals like soda ash (sodium carbonate) may be more appropriate depending on whether you’re trying to raise pH without significantly affecting alkalinity.
Combining Baking Soda with Other Pool Chemicals
To maintain a fully balanced pool, baking soda is rarely used in isolation. You’ll often add it alongside other important chemicals:
Chlorine:
Sanitizes the water and controls bacteria and algae.
pH Increaser/Decreaser:
Adjusts the actual pH level of the water, often in conjunction with TA adjustments.
Cyanuric Acid (Stabilizer):
Helps protect chlorine from UV degradation.
Calcium Hardness Increaser:
Maintains required hardness levels for water comfort and equipment health.
Always test your chemistry panel as a whole before making any adjustments to avoid over-correction. The balance of your pool water depends on all levels working together.
Real-Life Scenario: Raising TA from 60 ppm to 100 ppm in a 20,000 Gallon Pool
Let’s walk through a practical example to illustrate how real-world pool chemistry management works.
Background:
- Pool type: Vinyl above-ground chlorine pool
- Volume: 20,000 gallons
- Current total alkalinity: 60 ppm
- Target alkalinity: 100 ppm
Goal:
Raise total alkalinity by 40 ppm.
Calculation:
- For every 10 ppm increase, you need 2 pounds of baking soda.
- For a 40 ppm increase = 2 pounds * 4 = 8 pounds
Summary Outcome:
Dissolve and add 8 pounds of pure sodium bicarbonate, preferably in a few stages over the course of a few days, and retest between applications.
Post-Addition Care:
Run the pool pump continuously for 8 hours after each addition. Wait 24 hours to fully assess the change.
Maintaining Proper Total Alkalinity Over Time
Adding baking soda isn’t a one-time fix. Total alkalinity can fluctuate due to several factors:
- Frequent swimmer use
- Heavy rain or evaporation
- Chemical additions (chlorine, shock treatments, acids)
- Environmental debris — leaves, dirt, pollen
To preserve a stable alkalinity level:
- Test your water weekly, especially during peak swimming season.
- Address drops in alkalinity quickly before water balance becomes unstable.
- Use a combination of baking soda, pH modifiers, and proper filtration for optimal chemistry.
- Keep detailed records of chemical additions and test results for future reference.
A proactive approach to pool chemistry ensures longer equipment life, crystal clear water, and a more enjoyable swim.
Conclusion
Maintaining total alkalinity in a 20,000-gallon pool is a vital aspect of water balance, and baking soda is one of the best tools available for this task. The general dosage required is approximately 2 pounds of pure sodium bicarbonate per 10 ppm increase in TA. Depending on your starting point, you may need 2 to 8 pounds, or even more in extreme cases.
The key steps are always:
- Test your current alkalinity.
- Calculate the required increase.
- Add baking soda accordingly and allow time for it to circulate and dissolve.
- Retest after 24 hours.
And always choose the correct type of baking soda — ideally, pool-grade sodium bicarbonate designed for water chemistry adjustments.
When done consistently and correctly, managing TA with baking soda can help you enjoy clear, comfortable, and safe swimming conditions all season long. And now you’re fully equipped to handle that 20,000-gallon pool with confidence.
By staying on top of your pool’s alkalinity needs, you’ll avoid costly problems, extend the life of your pool equipment, and create a better swimming environment for everyone — which is the true goal of any conscientious pool owner or manager.
How much baking soda do I need for a 20,000 gallon pool?
To raise the alkalinity of your pool water, a general guideline is that 1.5 pounds of baking soda (sodium bicarbonate) will raise the alkalinity by about 10 parts per million (ppm) in 10,000 gallons of water. Therefore, for a 20,000 gallon pool, you would need approximately 3 pounds of baking soda to achieve the same 10 ppm increase. This calculation assumes your pool’s current alkalinity is low and you’re aiming to bring it into the recommended range of 80–120 ppm.
It’s important to test your pool water before adding any chemicals. If your alkalinity is already within or above the optimal range, adding more baking soda could cause the pH and alkalinity to become too high, which may lead to cloudy water or scaling. After adding baking soda, allow the water to circulate for at least six hours before retesting for accurate results.
Can I use baking soda instead of alkalinity increaser in my pool?
Yes, baking soda can be used as an alternative to commercial alkalinity increasers because it contains sodium bicarbonate, which is the primary ingredient in most of these products. It’s a cost-effective and readily available option for adjusting total alkalinity in pool water. However, it’s important to ensure the baking soda you use is pure and free of additives like fragrances or detergents.
While both products function similarly, some pool-specific alkalinity increasers may be more finely tuned to work with pool chemistry without affecting the pH too drastically. Baking soda does raise pH slightly, so it’s best used when both alkalinity and pH are low. Always test your water before making adjustments and monitor the levels closely after application to avoid overcorrection.
Will adding baking soda to my pool make the water cloudy?
Adding baking soda directly to your pool water shouldn’t cause cloudiness if it’s added in the correct amounts and mixed properly. However, if you add too much at once or don’t let it dissolve fully before turning your filtration system back on, it can result in temporary cloudiness due to undissolved particles in the water. Cloudiness can also occur if your pool water becomes oversaturated with minerals due to high alkalinity or pH.
To avoid cloudiness, always pre-dissolve baking soda in a bucket of water before adding it to the pool, and do it during a time when you can allow the pool to circulate for several hours afterward. If the cloudiness persists after 24–48 hours and the chemical balance has been stabilized, you may need to investigate other sources, such as calcium hardness or debris in the water.
How often should I add baking soda to my pool?
The frequency with which you should add baking soda depends on the size of your pool and how often the alkalinity drops below the recommended range of 80–120 ppm. For a 20,000 gallon pool, some pool owners may need to add baking soda every few weeks, especially after heavy usage, heavy rain, or significant water replacement.
Regular water testing—at least once a week—is essential to monitor alkalinity and pH levels. If the alkalinity starts to drop below the recommended level, small adjustments with baking soda or a commercial increaser can be made. Adding baking soda too frequently or in large amounts could lead to over-stabilization, requiring partial draining and refilling to correct.
Does baking soda affect the pH of pool water?
Yes, baking soda does have an impact on the pH of pool water, but it’s considered a mild alkalinity increaser and pH buffer. Generally, when you add baking soda to your pool, it raises total alkalinity, which in turn helps stabilize the pH level. The ideal pH range for pool water is 7.4–7.6, and maintaining proper alkalinity is critical to preventing pH fluctuations.
While baking soda can raise pH slightly, it’s not as strong as soda ash (sodium carbonate), which is commonly used to specifically raise pH without significantly affecting alkalinity. If both pH and alkalinity are low, baking soda is a good solution. However, for isolated pH issues, other chemicals may be more appropriate. Always test your water before deciding on which chemical to use.
How long should I wait to swim after adding baking soda to my pool?
It’s generally safe to swim in your pool about 6 to 8 hours after adding baking soda, assuming the water has had enough time to circulate and fully dissolve the chemical. This time frame allows for even distribution throughout the pool and minimizes the risk of exposure to concentrated chemical pockets, which could potentially irritate the skin or eyes.
However, if you pre-dissolved the baking soda before adding it and your pool’s pump is running efficiently, you could wait as little as 2–4 hours. As a best practice, retest the water before swimming to make sure the pH and alkalinity levels are balanced within the acceptable range, and always ensure the baking soda is completely dispersed.
Can I add baking soda to a vinyl, concrete, or fiberglass pool?
Yes, baking soda is safe to use in all types of pools, including vinyl, concrete (plaster), and fiberglass surfaces. It is a mild chemical and does not cause damage to these materials when used correctly. As with any pool chemical, it’s important to avoid adding large amounts directly onto the pool surface, as this can result in localized high pH or alkalinity levels that might cause staining or scaling over time.
It is best to add baking soda in a pre-dissolved state and disperse it evenly around the pool while the filtration system is running. This ensures the chemical integrates safely with the pool water without creating concentrated areas that could affect either the water chemistry or the pool surface integrity. Always rinse off any residual powder that may settle on the sides or bottom of the pool to prevent buildup.