To raise pool pH, add sodium carbonate (soda ash) for a direct pH boost or sodium bicarbonate (baking soda) to raise alkalinity first.
Most people hear “pH” and think of their own body—alkaline water, special diets, that sort of thing. So when a pool test strip comes back with a reading of 6.8, the instinct might be to grab whatever sounds “natural.” But pool water is its own chemistry project, and the rules are different.
The standard way to raise pH in a swimming pool involves choosing between two common pool chemicals: soda ash and baking soda. Getting it right means understanding how each one affects not just pH, but total alkalinity too. This guide walks through the step-by-step process, the tools you need, and how to keep the water balanced so it stays comfortable for swimmers and safe for equipment.
Why Pool pH Gets Low in the First Place
Several factors can push pH downward. Heavy rainfall introduces acidic water. Swimmers themselves contribute—sweat, sunscreen, and body oils all interact with chlorine and gradually lower pH. Even the sanitizer you use matters; liquid chlorine and trichlor tablets are acidic by nature.
Low pH isn’t just a number on a test strip. It causes noticeable problems. Swimmers often complain about burning eyes or itchy, irritated skin. The water itself may take on a greenish tint. More seriously, acidic water can corrode metal pool components like heaters and ladder brackets, and it can etch plaster or gunite surfaces over time.
Catching it early is simple. A reliable test kit or digital tester gives a clear reading. If the number falls below 7.2, you have a strong sign it’s time to take action.
Understanding the pH-Alkalinity Relationship
Many pool owners make the same mistake: they try to adjust pH without first checking total alkalinity (TA). TA measures the water’s ability to resist pH changes. Think of it as a buffer. When TA is in the sweet spot, pH stays stable.
- Ideal pH Range: 7.4 to 7.6. This range is optimal for swimmer comfort and chlorine effectiveness.
- Ideal TA Range: 80 to 120 ppm. Within this zone, pH remains relatively steady against environmental changes.
- TA Too Low: When TA drops, the water has no buffering capacity. pH swings wildly with any chemical addition or rainfall.
- TA Too High: Excess alkalinity can cause pH to creep upward over time, leading to scale formation on pool surfaces and equipment.
- The Rule of Thumb: Adjust total alkalinity first. Once TA is within the ideal range, pH becomes much easier to dial in and hold steady.
This relationship is why simply throwing baking soda into the water without testing can create a new problem. You might raise TA too high, which then pushes pH up past 7.8 and into scaling territory.
Soda Ash vs. Baking Soda — Which One Should You Use
Per the ideal pool pH range guide from Maytronics, the distinction between the two chemicals comes down to your specific test results. If the pH is low (below 7.4) but total alkalinity is within the ideal 80-120 ppm range, soda ash is the better choice. It delivers a strong, direct boost to pH without pushing alkalinity out of whack.
If both pH and TA are low, start with baking soda. Its primary job is to raise total alkalinity. As TA climbs into range, pH will naturally follow it upward. This is the safer approach because it avoids large pH swings and provides a stable baseline.
A common rule of thumb is 1.5 pounds of baking soda per 10,000 gallons of water to raise TA by about 10 ppm. For soda ash, smaller doses are needed because it’s more concentrated. Always pre-dissolve soda ash in a bucket of water first to prevent cloudiness or undissolved granules from settling.
| Feature | Sodium Carbonate (Soda Ash) | Sodium Bicarbonate (Baking Soda) |
|---|---|---|
| Primary Effect | Raises pH quickly and strongly | Raises Total Alkalinity (mild pH effect) |
| Best Use Case | Low pH, TA already in range | Low TA (and pH is slightly low) |
| Dosage Strength | More potent per pound | Milder, needs larger volume |
| Preparation | Pre-dissolve in water bucket | Can broadcast directly into deep end |
| Price | More expensive per pound | Typically cheaper per pound |
Having a clear strategy prevents the common error of adding the wrong chemical. One quick test can save you a week of cloudy water.
Step-by-Step Guide to Raising pH Safely
The right chemical is only half the equation. The method of application matters just as much. Follow these steps to avoid cloudiness, staining, or overshooting the target.
- Test the water thoroughly. Use a liquid test kit or digital reader to get both pH and TA readings before adding anything.
- Choose your chemical. Decide between soda ash or baking soda based on the relationship between your current pH and TA levels.
- Calculate the dose. Follow manufacturer instructions on the product label. For baking soda, 1.5 lbs per 10,000 gallons is a common starting point to adjust TA.
- Apply the chemical correctly. For baking soda, walk around the pool’s deep end and broadcast it evenly. For soda ash, mix it in a bucket with water and pour the solution around the perimeter.
- Run the pump and retest. After adding the chemical, let the pump run for at least 6 to 8 hours. Retest both pH and TA before making any further adjustments.
Patience is the hardest part of pool chemistry. Making small incremental changes and waiting for the water to circulate prevents the constant up-and-down cycle that frustrates many owners.
Common Mistakes and How to Avoid Them
Many well-intentioned pool owners add chemicals and check the reading too soon. The water hasn’t mixed yet. Run pump after adding chemicals is the standard advice from pool maintenance guides. Give it a full cycle before trusting the test result.
Another common error is adding both a pH increaser and an alkalinity increaser at the same time. They target different things but overlap chemically. Chase one number at a time. Fix TA first, then address pH if it’s still off from the target zone.
Finally, many people forget to pre-dissolve soda ash. Dry granules of soda ash can sink to the floor and etch the plaster or leave white spots. A bucket of water solves this easily. Small doses, patience, and retesting lead to a consistently clear pool.
| Symptom | Likely Cause | First Step |
|---|---|---|
| Burning eyes, pH below 7.2 | Low pH (possible low TA) | Test TA, add baking soda if TA is low |
| Water greenish, pH low | Low pH (possible algae) | Adjust pH to 7.4-7.6, then shock |
| Scale on tiles, pH above 7.8 | High pH (possible high TA) | Use pH reducer, check TA |
The Bottom Line
Raising pool pH isn’t complicated, but it does require a test kit and a little patience. The key distinction is between soda ash for a direct pH boost and baking soda for fixing total alkalinity first. Stick to the ideal ranges—pH 7.4-7.6 and TA 80-120 ppm—and your water will stay balanced.
If you’re unsure about your specific pool’s gallon capacity or test results after a few attempts, taking a water sample to a local pool supply store can clarify exactly which chemical and dose you need for your volume and conditions.
References & Sources
- Maytronics. “How to Raise Andlower the Ph Balance in Your Pool” PH is a measure of how acidic or basic the water is, with the ideal range for a swimming pool being between 7.4 and 7.6.
- Netpositivepools. “How to Raise Ph in Pool” After adding chemicals, run the pool pump for at least 6–8 hours to circulate the water, then retest the pH and alkalinity levels.