If you own a pool, you know how important it is to maintain the water quality. One of the key factors that affect water quality is the pH level, which measures how acidic or alkaline the water is. The ideal pH range for pools is 7.2 to 7.6, which is slightly alkaline and comfortable for swimmers.

However, sometimes the pH level can drop below this range, causing problems such as corrosion, irritation, and chlorine inefficiency. In this article, we will explain what causes low pH in pool water, how to test it, and how to raise it using different methods.

What Causes Low pH in Pool Water?

The pH level of pool water can change due to various factors, such as:

• Rainwater: Rainwater is naturally acidic and can lower the pH of your pool water when it mixes with it.
• Debris: Leaves, dirt, insects, and other organic matter can also introduce acidity into your pool water as they decompose.
• Chemicals: Some pool chemicals, such as chlorine and algaecides, can lower the pH of your pool water as they react with it.
• Swimmers: Swimmers can also affect the pH of your pool water by introducing sweat, urine, cosmetics, and other substances that can alter the water’s chemistry.

How to Test pH in Pool Water?

To test the pH level of your pool water, you will need a test kit or a test strip that measures pH. You can find these at any pool supply store or online. To use a test kit or a test strip, follow these steps:

• Collect a water sample from your pool using a clean container. Avoid taking samples near the skimmers or the jets, as they can affect the accuracy of the test. Ideally, you should take a sample from the middle of your pool at elbow depth.
• Dip the test strip or add the reagent to the water sample according to the instructions on the package. Wait for a few seconds for the color to develop.
• Compare the color of the test strip or the water sample with the color chart provided with the test kit or the test strip. The color will indicate the pH level of your pool water. If the color is yellow or orange, it means your pH is low. If the color is blue or purple, it means your pH is high. If the color is green, it means your pH is ideal.

You should test your pool water at least once a week or more often if you use your pool frequently or if there are changes in weather or water conditions.

How to Raise pH in Pool Water?

If your test results show that your pH level is low, you will need to raise it using one of these methods:

Soda Ash

Soda ash (or sodium carbonate) is a common chemical that can raise both the pH and the alkalinity of your pool water. Alkalinity is a measure of how well your pool water can resist changes in pH. You can buy soda ash at any pool supply store or online. To use soda ash, follow these steps:

• Calculate how much soda ash you need to add to your pool using an online calculator² or by following the instructions on the package. The amount will depend on the size of your pool and how much you need to raise the pH.
• Dissolve the soda ash in a bucket of warm water before adding it to your pool. This will prevent the clumping and clouding of your pool water.
• Pour the solution into your pool slowly and evenly around the perimeter. Avoid pouring it near metal fixtures or fittings, as soda ash can cause staining.
• Run your pool pump and filter for at least four hours to circulate and distribute the soda ash throughout your pool.
• Test your pool water again after 24 hours to check if the pH level has reached the desired range. If not, repeat the process until it does.

Baking Soda

Baking soda (or sodium bicarbonate) is another chemical that can raise both the pH and the alkalinity of your pool water. However, baking soda is less effective than soda ash at raising pH, so you will need to use more of it. You can buy baking soda at any grocery store or online. To use baking soda, follow these steps:

• Calculate how much baking soda you need to add to your pool using an online calculator or by following the instructions on the package. The amount will depend on the size of your pool and how much you need to raise the pH.
• Dissolve the baking soda in a bucket of warm water before adding it to your pool. This will prevent the clumping and clouding of your pool water.
• Pour the solution into your pool slowly and evenly around the perimeter. Avoid pouring it near metal fixtures or fittings, as baking soda can cause staining.
• Run your pool pump and filter for at least four hours to circulate and distribute the baking soda throughout your pool.
• Test your pool water again after 24 hours to check if the pH level has reached the desired range. If not, repeat the process until it does.

Aeration

Aeration is a natural and simple way to raise the pH of your pool water by exposing it to air. Aeration causes carbon dioxide to escape from your pool water, which reduces the acidity and increases the pH. You can aerate your pool water by using any of these methods:

• Turn on your pool jets, fountains, waterfalls, or other features that create water movement and splashing.
• Use a pool aerator, which is a device that attaches to your pool return and creates bubbles in your pool water.
• Use a pool brush or a leaf blower to agitate the surface of your pool water.
• Use an air compressor or a hose to spray air into your pool water.

You should aerate your pool water for several hours or until you notice a change in the pH level. You can also combine aeration with soda ash or baking soda to speed up the process.

How to Prevent Low pH in Pool Water?

To prevent low pH in your pool water, you should follow these tips:

• Test your pool water regularly and adjust the pH as needed.
• Use a pH stabilizer, which is a chemical that helps maintain a constant pH level in your pool water.
• Keep your pool clean and free of debris that can lower the pH.
• Balance other pool chemicals, such as chlorine and cyanuric acid, that can affect the pH.
• Avoid adding too much acid or chlorine to your pool, as they can lower the pH.
• Cover your pool when not in use to reduce evaporation and rainwater dilution.

Conclusion

Maintaining the pH level of your pool water is essential for the health and comfort of you and your swimmers. By testing your pool water regularly and using one of the methods described above, you can easily raise the pH of your pool water when it is low. Remember to always follow the instructions on the package of any chemical you use and wear protective gear when handling them. Happy swimming!