How to Fix High pH in Your Pool

Add muriatic acid in small increments to lower the pH to the ideal range of 7.2-7.6.

What Causes High pH in Your Pool?

Before addressing how to lower the pH in your pool, it’s important to understand what causes high pH levels. Knowing the cause can help prevent the issue from recurring in the future.

1. Adding Alkaline Chemicals

Certain pool chemicals, especially chlorine tablets, can raise pH levels. For example, many pool sanitizers are alkaline, meaning that they can cause pH to rise when overused or improperly stored.

• Chlorine Tablets: While effective at sanitizing your pool, chlorine tablets can increase your pool’s pH over time if they are added in large quantities.

• Other Alkaline Pool Chemicals: Baking soda and some other pool chemicals that raise alkalinity can also indirectly raise pH.

2. Hard Water

If your pool uses hard water (water that has a high mineral content), it may naturally have a higher pH level. The high levels of calcium and other minerals can cause the pH to rise, making the water more alkaline.

• What is Hard Water?: Hard water is water that contains high amounts of calcium and magnesium. These minerals can contribute to scaling on your pool’s surface and raise the pH.

• Sources of Hard Water: If you’re using well water or certain municipal sources that have high mineral content, this could contribute to higher pH levels.

3. Rainwater

Rain can cause fluctuations in your pool’s pH level. While rainwater is typically neutral, it can become slightly alkaline when mixed with pollutants in the air or when rainwater contains a higher mineral concentration.

• Heavy Rainfall: Sudden heavy rain can wash in pollutants, causing a rise in the pH.

• How to Prevent This: Consider covering your pool during heavy storms to reduce the effects of rainfall on your pH level.

4. Evaporation

As water evaporates from the pool, the concentration of pool chemicals increases. This can lead to an increase in pH if the pool water is evaporating too quickly.

• High Temperatures: Hot weather and high temperatures can accelerate evaporation, which causes a concentration of chemicals.

• What to Do: To prevent this, keep your pool covered when not in use during hot periods to limit evaporation and prevent pH buildup.

5. High Alkalinity

A high alkalinity level often goes hand-in-hand with a high pH. The total alkalinity of your pool is responsible for stabilizing pH, and when it’s too high, it makes it harder to bring pH levels down.

• Ideal Alkalinity Range: Alkalinity levels should generally fall between 80 and 120 ppm. If your alkalinity is above that range, it can cause pH to rise as well.

How to Test pH Levels in Your Pool

Before taking any corrective action, it’s important to accurately measure the pH level in your pool to confirm it is too high. Here’s how to test your pool’s pH level:

1. Use a Pool Test Kit

You can use either a liquid test kit or test strips to measure your pool’s pH level. Test strips are easy to use and provide quick results, while liquid kits tend to offer more precise measurements.

• Liquid Test Kits: Liquid test kits are more accurate and provide a better overall picture of your pool water’s condition.

• Test Strips: These are convenient and fast, making them a great option for quick checks.

2. Test the Water at Multiple Points

Make sure to test the water in several areas of the pool to ensure an accurate reading. pH levels can vary slightly in different parts of the pool.

• Different Areas: Test near the skimmer, return jets, and center of the pool to get a complete view of your pH levels.

3. Understand the Ideal pH Range

The ideal pH level for pool water is between 7.4 and 7.6. If your pool pH is above 7.8, it’s considered high and will need adjustment.

How to Lower pH in Your Pool

Once you’ve confirmed that your pool’s pH is too high, it’s time to take action. Lowering pH in your pool requires the right chemicals and correct application. Follow these steps to bring your pool’s pH levels down to the desired range.

1. Add pH Reducers (Acid)

The most common and effective way to lower pH in a pool is by adding a pH reducer. pH reducers, also called pH decreasers, are typically made of muriatic acid or dry acid.

• Muriatic Acid: This is a liquid acid that works quickly and effectively to lower pH. It’s the most commonly used acid for pool treatment.

• Dry Acid (Sodium Bisulfate): This is a safer alternative to muriatic acid and is easier to handle. Dry acid dissolves quickly in the pool water and begins to reduce pH levels immediately.

Tip: Always add pH reducer to the pool in small amounts and re-test the pH after a few hours to avoid over-correction.

2. Dilute the Acid Before Adding

When adding acid to your pool, it’s important to dilute it with water to avoid concentrated chemical damage to the pool surface.

• For Muriatic Acid: Mix the acid with a gallon of pool water in a bucket before adding it to the pool. This helps distribute the acid evenly and prevents staining or damage to pool surfaces.

• For Dry Acid: Follow the manufacturer’s guidelines for the proper dilution ratio.

3. Add Acid Slowly and in Small Doses

Always add the acid slowly and in small doses to prevent sudden changes in water chemistry. Pour the diluted acid around the pool’s edge, allowing it to disperse naturally.

• Tip: Avoid adding acid near the skimmer or pool equipment to prevent damage. Walk around the pool as you pour the acid to ensure even distribution.

4. Wait and Retest the pH

After adding the acid to the pool, allow the water to circulate for at least 4 hours before testing the pH again. It’s important not to overcorrect and cause the pH to drop too low.

• Tip: If your pH is still high, you may need to add additional doses of acid. Always make adjustments slowly and test frequently.

5. Regularly Monitor pH Levels

Once you’ve adjusted the pH, continue to monitor your pool water regularly to ensure it stays within the ideal range.

• Test at least once a week: Pool water chemistry can fluctuate, so testing your pH at least once a week will help you stay on top of any potential imbalances.

• Check after adding chemicals: Always check the pH after adding any chemicals to your pool to ensure that it hasn’t shifted too much.

6. Prevent Future pH Imbalances

To avoid dealing with high pH in the future, consider these preventative measures:

• Proper chemical balance: Make sure your alkalinity is within the recommended range (80-120 ppm) since high alkalinity can cause pH levels to rise.

• Use appropriate pool chemicals: Use pool chemicals according to the manufacturer’s instructions. Avoid adding too many alkaline chemicals or excessive amounts of pool products.

• Check water source: If you are filling your pool with hard water or mineral-rich water, consider using a pre-filter to reduce the mineral load.

Tip: Regularly clean your pool’s filter and skimmer baskets to maintain proper water circulation and filtration, which can help prevent pH imbalances.