How To Increase The Alkalinity In My Pool | Simple Pool Care

Pool water looks blue and clear one day, then turns cloudy or causes eye irritation the next. You test the water, and the pH is bouncing all over the place. The culprit is often low total alkalinity — the water’s buffer against sudden acid shifts.

This guide walks through the practical steps to raise your pool’s alkalinity safely, the right chemicals to use, and how to avoid common mistakes that leave your water out of balance.

What Total Alkalinity Does For Your Pool

Total alkalinity (TA) measures your water’s ability to neutralize acids. Think of it as a shock absorber that stops pH from swinging wildly every time someone jumps in or rain falls.

When TA drops too low, your pH becomes unstable. A little bit of chlorine or a splash of acid sends it crashing down, which can corrode metal fixtures and irritate swimmers’ skin.

On the flip side, TA that is too high can make pH drift upward, reducing chlorine’s effectiveness. Keeping TA in the recommended range — roughly 80 to 100 ppm for most pools — gives you a stable baseline for all other chemical adjustments.

Why Pool Owners Miss Low Alkalinity

Many pool owners test pH regularly but skip the TA reading entirely. Low alkalinity doesn’t always cause obvious symptoms right away, so it’s easy to overlook until bigger problems emerge.

• Cloudy water: Low TA lets pH fluctuate, which can cause calcium to fall out of solution and cloud the water.
• Corroded equipment: Acidic water from unstable pH attacks metal ladders, pump parts, and heater coils over time.
• Eye and skin irritation: Rapid pH changes create water that stings swimmers’ eyes and dries out skin.
• Chlorine inefficiency: Unstable pH forces chlorine to work harder, meaning you may need to add more sanitizer than usual.
• Scale formation: High pH spikes from low TA can trigger calcium scaling on tile and plaster surfaces.

Testing alkalinity once a week with a reliable test kit or test strips is the simplest way to catch these issues before they compound. Most pool owners confirm that regular testing prevents far more maintenance down the line.

Choosing Between Baking Soda And Soda Ash

Two common chemicals raise total alkalinity, and the right choice depends on what else your water needs. The industry standard is to use sodium bicarbonate (baking soda) for alkalinity and sodium carbonate (soda ash) for pH, as explained in the total alkalinity definition from Frogproducts.

Baking soda raises TA with a minimal effect on pH. That makes it the go-to when your alkalinity is low but your pH is already in the 7.4 to 7.6 sweet spot. If you test and see TA at 60 ppm with pH at 7.5, baking soda solves the problem without creating a new one.

Soda ash raises both pH and TA. Use it when your TA is low and your pH has also dropped below 7.2. A common approach is to add 3 to 4 pounds of baking soda per 10,000 gallons if pH is below 7.2, since that dose lifts both numbers together. Commercial alkalinity increaser products are essentially the same chemical as baking soda, so there’s no advantage to paying more for a branded version.

Test your water before adding anything. Knowing where your pH and TA currently sit determines which chemical to buy and how much to add.

Step-By-Step Process To Raise Alkalinity

Raising alkalinity is straightforward, but rushing the process or skipping the wait time between doses can overshoot your target.

1. Test your current TA and pH. Use a reliable liquid test kit or test strips. Write down the numbers before adding anything.
2. Calculate your pool volume. Measure length, width, and average depth. Multiply length × width × average depth × 7.5 for gallons. Or use an online pool volume calculator.
3. Measure the right dose. The common rule is 1.5 pounds of baking soda per 10,000 gallons to raise TA by about 10 ppm. Adjust the dose proportionally for your pool size.
4. Pre-dissolve the powder. Mix the baking soda in a bucket of pool water until dissolved, then pour it evenly around the pool’s perimeter. This prevents clumps from sinking to the floor.
5. Run the pump and wait. Keep the pump running for at least 4 to 6 hours with the filter on recirculate. Retest TA after 24 hours before making another adjustment.

Raising too much at once can push alkalinity above 150 ppm, which makes pH drift high and creates scale. It’s easier to add a second small dose than to lower high TA with muriatic acid.

Common Questions About Alkalinity Adjustment

New pool owners often wonder about the relationship between pH and alkalinity, especially when they test and one number is off but the other looks fine. Baking soda raises TA without significantly raising pH, making it the standard for alkalinity-only adjustments.

Soda ash, by contrast, will lift both. According to the soda ash effect on pH, six ounces of soda ash per 10,000 gallons raises alkalinity by about 5 ppm while also pushing pH upward. That dual action makes it useful for pools where both numbers are low, but it is less precise when you only need TA adjustment.

For pools with saltwater chlorine generators (SWG), some owners target a slightly higher TA range of 110 to 120 ppm to help stabilize pH. The trade-off is that this higher alkalinity may require more frequent acid additions. Test weekly and adjust based on your pool’s specific behavior.

If you’ve been dumping chlorine tablets or muriatic acid regularly, those products themselves can lower TA over time. Heavy rain can also dilute your water, dropping both TA and pH.

The Bottom Line

Raising pool alkalinity starts with a simple test and a calculated dose of baking soda. The standard approach — 1.5 pounds per 10,000 gallons to gain about 10 ppm — works for most residential pools. Always retest after 24 hours before adding more, and match your chemical choice to what your pH is doing.

A local pool supply store or pool service professional can check your specific water chemistry and help you dial in the right target for your sanitizer type, climate, and equipment.