How to Lower Alkalinity in a Pool Quickly: A Complete Guide by AQUASTRONG

If you've noticed that your pool’s total alkalinity is higher than the ideal range of 80–120 ppm, don’t worry—it’s an easy fix. High alkalinity can affect the water chemistry and overall pool health, but with a few simple steps, you can restore balance to your pool. This guide will walk you through how to lower alkalinity using common pool chemicals like muriatic acid or sodium bisulfate (pH reducer), and help you understand why alkalinity can rise in the first place.

What is Total Alkalinity?

Total alkalinity refers to the water’s ability to buffer pH changes. Essentially, it stabilizes your pool's pH levels and helps prevent drastic fluctuations. Maintaining balanced alkalinity is crucial for proper water chemistry, as high or low alkalinity can impact everything from chlorine effectiveness to swimmer comfort.

For optimal pool care, the total alkalinity should fall between 80–120 ppm, with a pH range between 7.2 and 7.8. When either of these levels is too high or too low, it can lead to issues like cloudy water, poor chlorine efficiency, and potential damage to pool equipment.

How Does High Alkalinity Affect Pool Water?

High alkalinity can cause several problems in your pool:

• Raises pH Levels: When alkalinity is too high, pH levels tend to increase, often above the ideal range. This can lead to scaling and cloudy water.
• Reduces Chlorine Effectiveness: Elevated pH and alkalinity can make chlorine less effective at sanitizing the water, leaving your pool vulnerable to contaminants.
• Irritates Skin and Eyes: Swimmers may experience itchy skin and red, burning eyes when pH and alkalinity are unbalanced.
• Causes Scale Buildup: High alkalinity can lead to calcium deposits forming on the pool surface and inside the plumbing, affecting water flow and pool circulation.

What Causes High Total Alkalinity?

Several factors can contribute to elevated alkalinity levels in your pool, including:

• Pool Chemicals: Certain pool chemicals, such as stabilizers like cyanuric acid (CYA), can increase alkalinity. CYA helps protect chlorine from being degraded by UV rays but can also buffer acidic chlorine, raising alkalinity over time.
• Low Chlorine Levels: If your pool has low chlorine and many swimmers, the buildup of contaminants can cause pH and alkalinity levels to rise.
• Pool Shock: Regularly shocking your pool with chlorine-based shock treatments can raise alkalinity. These chemicals are highly alkaline and may affect both your pH and alkalinity.

By regularly testing your pool's water chemistry, you can stay on top of these changes and prevent alkalinity from becoming a problem.

How to Lower Alkalinity in Your Pool

There are two primary methods for lowering high alkalinity: muriatic acid and sodium bisulfate (pH reducer). Keep in mind that both of these methods will also lower your pool's pH levels, so it’s essential to monitor both values during the treatment process.

Option 1: Lowering Alkalinity with Muriatic Acid

Muriatic acid, a common pool chemical, is one of the most effective ways to lower alkalinity. It’s a diluted form of hydrochloric acid that, when added to your pool, helps bring both alkalinity and pH into balance. However, muriatic acid is highly corrosive, so take proper precautions when handling it.

Steps to Use Muriatic Acid:

1. Turn off the Pool Pump: Before adding any chemicals, ensure the pool pump is off, and the water has completely stopped moving.
2. Calculate the Amount of Muriatic Acid: As a general rule, you’ll need about 25.6 ounces (750 mL) of full-strength muriatic acid to reduce the alkalinity of a 10,000-gallon pool by 10 ppm.
3. Add the Acid: Carefully pour the acid into the deepest part of the pool. Avoid splashing, and wear appropriate safety gear (gloves, mask, and goggles).
4. Turn on the Pump: Once the acid is added, turn on the pool pump and allow it to circulate for at least 5 hours.
5. Test the Water: After the circulation time, retest the water for alkalinity and pH levels. If needed, repeat the process to reach the desired levels.

Option 2: Lowering Alkalinity with Sodium Bisulfate (Dry Acid)

Sodium bisulfate, also known as dry acid, is another effective option to lower alkalinity. It’s less hazardous than muriatic acid and works similarly to reduce both pH and alkalinity.

Steps to Use Sodium Bisulfate:

1. Mix the Chemical: Fill a clean bucket with water (3/4 full) and add the recommended amount of sodium bisulfate according to the product instructions.
2. Dissolve the Acid: Stir the mixture until all the granules are completely dissolved. Undissolved particles can damage your pool surface.
3. Add to Pool: Carefully pour the dissolved solution around the perimeter of the pool, starting with the deep end.
4. Test the Water: Allow the pool to circulate for a few hours, then test the water’s alkalinity and pH. Repeat the process if necessary.

Important Tips for Lowering Alkalinity

• Add Acid Gradually: Always add acid in small amounts, testing frequently. It’s better to add less and retest than to overdo it and risk overshooting the target range.
• Aeration: If you accidentally lower your pool's pH too much during this process, you can raise the pH by aerating the pool. Simply run the pool jets or use an aerator to introduce air into the water. This will increase pH without affecting alkalinity.

Conclusion

Maintaining balanced alkalinity in your pool is key to ensuring clean, safe, and comfortable water for swimmers. By using muriatic acid or sodium bisulfate, you can quickly lower high alkalinity and restore proper pool chemistry. Always remember to test your water frequently and follow the recommended guidelines to keep your pool in top condition.

For more expert tips and high-quality pool products to maintain a healthy pool, visit AQUASTRONG today. We’re here to help you keep your pool clear, balanced, and ready for fun all year round.