How to Raise Pool Alkalinity: Complete Step-by-Step Guide

Tools & Supplies Needed

Find on Amazon: Taylor K-2006C Pool Test Kit , Pure Sodium Bicarbonate , Digital Pool Water Tester

Quick Answer

The most effective way to raise pool alkalinity is by adding sodium bicarbonate (baking soda). For every 10 ppm increase needed, add approximately 1.5 pounds of sodium bicarbonate per 10,000 gallons of pool water. Always test your current alkalinity level first, add chemicals with the circulation system running, and retest after 6 hours of circulation.

Understanding Pool Alkalinity

Total alkalinity (TA) acts as a pH buffer, preventing rapid pH swings that can damage equipment and make chlorine less effective. The ideal alkalinity range is 80-120 ppm for traditional chlorine pools and 60-80 ppm for salt water generator pools. Low alkalinity causes pH to bounce erratically, leading to equipment corrosion, plaster etching, and swimmer discomfort.

Testing Your Current Alkalinity Level

Before adding any chemicals, you need an accurate baseline reading. Use a reliable test kit like the Taylor K-2006C or a quality digital tester. Pool store test strips are notoriously unreliable for alkalinity readings. Test your water in the morning before the sun affects the chemistry, and ensure your hands are clean to avoid contaminating the sample.

If your alkalinity is below 80 ppm (or 60 ppm for salt water pools), you'll need to raise it. Calculate the difference between your current level and target level to determine how much sodium bicarbonate to add.

Calculating Sodium Bicarbonate Dosage

Use this simple formula: Pounds of sodium bicarbonate needed = (Target TA - Current TA) × Pool Volume ÷ 10,000 × 1.5

For example, if your 20,000-gallon pool tests at 50 ppm and you want to reach 90 ppm:

• (90 - 50) × 20,000 ÷ 10,000 × 1.5 = 12 pounds of sodium bicarbonate

For large adjustments over 20 ppm, split the addition into multiple doses over several days to avoid overshooting your target.

Step-by-Step Application Process

1. Turn on your circulation system - The pump should run throughout the entire process and for at least 6 hours afterward
2. Choose your sodium bicarbonate source - Pure baking soda from the grocery store works perfectly and costs less than pool-specific alkalinity increasers
3. Pre-dissolve if adding large amounts - For additions over 5 pounds, dissolve the sodium bicarbonate in a bucket of pool water first
4. Add gradually around the pool perimeter - Pour slowly while walking around the deep end, allowing the circulation system to distribute the chemical
5. Brush the pool bottom - Any undissolved particles should be brushed to help them dissolve completely
6. Wait before retesting - Allow 6-8 hours of circulation before testing again, as it takes time for the alkalinity to stabilize
7. Adjust pH if necessary - Adding sodium bicarbonate will also raise pH, so you may need to lower it with muriatic acid afterward

The pH Connection

Raising alkalinity will also increase your pH, typically by 0.2-0.4 units depending on your starting levels. This is normal and expected. After your alkalinity stabilizes, test your pH. If it's above 7.6, you'll need to lower it using muriatic acid. Add acid slowly and retest, as lowering pH will also slightly reduce alkalinity.

This pH-alkalinity relationship is why water balancing requires patience. Make one adjustment at a time and allow the chemistry to stabilize before making additional changes.

Alternative Products and Methods

While sodium bicarbonate is the preferred method, other options include:

• Sodium sesquicarbonate - Raises alkalinity with less pH impact but costs more
• Sodium carbonate (soda ash) - Primarily for pH but will slightly increase alkalinity
• Commercial alkalinity increasers - Usually sodium bicarbonate with a higher price tag

Avoid using calcium carbonate or lime, as these can cloud your water and create scaling issues.

Common Mistakes to Avoid

Don't dump chemicals in one spot - This can cause temporary high-concentration areas that may bleach vinyl liners or damage plaster.

Don't add multiple chemicals simultaneously - Wait at least 4 hours between different chemical additions to avoid unexpected reactions.

Don't rely on store water testing - Many pool stores use old reagents or untrained staff, leading to incorrect chemical recommendations.

Don't ignore circulation - Adding chemicals without proper circulation leads to uneven distribution and inaccurate test results.

Maintaining Proper Alkalinity Long-Term

Once you achieve proper alkalinity levels, maintaining them requires regular monitoring. Test weekly during swimming season and monthly during winter. Heavy rains can dilute alkalinity, while heavy bather loads and regular acid additions for pH control will gradually lower it.

Keep sodium bicarbonate on hand for minor adjustments. Small, frequent corrections are easier and more accurate than large, infrequent ones. A properly balanced pool with stable alkalinity will require fewer chemical adjustments overall, saving both time and money.