How Do I Fix High Alkalinity in my Pool?

Use muriatic acid or sodium bisulfate to gradually reduce alkalinity levels, retesting after each application.

Why is My Pool’s Alkalinity Too High?

High alkalinity is usually caused by an excess of alkaline substances in the water. This can happen due to several reasons:

• Overuse of Alkaline Pool Chemicals: Over-adding chemicals like sodium bicarbonate (baking soda) or alkaline-based pool treatments can raise alkalinity levels.
  

• High pH Levels: If your pool's pH level is too high, the alkalinity is likely to be elevated as well.
  

• Heavy Rainfall: Rainwater can introduce high amounts of dissolved minerals into your pool, which can increase alkalinity.
  

• Hard Water: Pools filled with hard water (high in calcium) can also have higher alkalinity levels.
  

How to Test for High Alkalinity

Before you can fix high alkalinity, you need to test your pool’s water to determine how high the alkalinity is. You can do this using a pool test kit or test strips.

• Test Kit: Follow the manufacturer’s instructions on how to collect a sample of your pool water and add it to the testing reagents. This will give you an accurate reading of the alkalinity levels.
  

• Test Strips: Pool test strips are easy to use and provide quick results. Simply dip the strip into the water and compare the color change to the provided chart to determine the alkalinity level.
  

Once you have the test results, you’ll know if your alkalinity is too high. If the reading is above 120 ppm, it’s time to take action.

How to Lower High Alkalinity in a Pool

If your test shows that your pool's alkalinity is too high, the good news is that it can be corrected by following these steps:

1. Add Muriatic Acid

The most common way to lower alkalinity is by using muriatic acid (hydrochloric acid), which reduces the alkalinity and brings the pH level into balance.

• Why You Need It: Muriatic acid helps lower the alkalinity by breaking down the alkaline substances in the water.
  

• How to Use It: First, dilute the muriatic acid by adding it to a large container of water (never add water to acid, always acid to water). Then, slowly pour the diluted acid into the pool, preferably near the return jets, to help disperse it evenly throughout the water.
  

• How Much to Add: Follow the instructions on the muriatic acid container to determine the correct amount to add based on your pool’s size and the test results. Typically, you'll need about 1 quart of muriatic acid for every 10,000 gallons of water to lower the alkalinity by 10 ppm.
  

• Tip: Wear protective gear, including gloves and goggles, when handling muriatic acid.
  

2. Add Sodium Bisulfate (Dry Acid)

If you prefer not to use muriatic acid, sodium bisulfate (also known as dry acid) is another option for lowering pool alkalinity.

• Why You Need It: Sodium bisulfate works in a similar way to muriatic acid by neutralizing alkaline substances in the water.
  

• How to Use It: Add sodium bisulfate to your pool water in the same way you would with muriatic acid, ideally near the return jets.
  

• How Much to Add: Typically, you'll need about 1 pound of sodium bisulfate for every 10,000 gallons of water to lower alkalinity by 10 ppm.
  

• Tip: Always follow the manufacturer’s guidelines for the proper amount of sodium bisulfate to use.
  

3. Aerate the Pool

Aeration is a natural method for lowering alkalinity. By increasing the aeration in your pool, you can lower both pH and alkalinity over time.

• Why You Need It: When you increase aeration, carbon dioxide is released into the atmosphere, which helps lower the alkalinity levels in the water.
  

• How to Aerate: Use a pool fountain, return jets, or a pool aerator to increase water movement and expose more of the water to air. This will gradually lower alkalinity.
  

• How Much to Use: Aeration alone won’t work quickly, but it’s a good method for gradual reduction. It can take several days or even weeks, depending on the severity of the alkalinity problem.
  

4. Test the Water Regularly

After you’ve made adjustments to the alkalinity, it’s essential to test the water regularly to ensure you’re not overcorrecting. Testing the water will allow you to track the progress and ensure that the levels are within the desired range.

• How Often to Test: Test the pool water every 24 hours after making changes to check the alkalinity levels.
  

• Adjust as Needed: If your alkalinity is still too high, repeat the steps above until it reaches the ideal range of 80-120 ppm.
  

Preventing High Alkalinity in the Future

Once you’ve corrected your pool’s high alkalinity, there are steps you can take to prevent it from happening again:

• Avoid Overusing Alkaline Chemicals: Be cautious when adding alkaline substances to your pool, and always follow the recommended dosage instructions.
  

• Maintain Proper pH: Keeping your pool’s pH level balanced will help keep the alkalinity in check as well.
  

• Monitor Pool Fill Water: If you’re using hard water to fill your pool, it may contribute to high alkalinity. Consider using softened water if possible.
  

• Use a Pool Cover: When the pool is not in use, keep it covered. This helps prevent rainwater from affecting the pool’s chemical balance.
  

By taking these preventive steps, you can help ensure your pool stays properly balanced and you won’t have to deal with high alkalinity issues in the future.

Additional Tips for Pool Water Balance

Proper pool maintenance involves more than just adjusting alkalinity. Here are a few tips to maintain overall water quality:

• Regularly Test Pool Chemicals: Besides alkalinity, regularly check pH, calcium hardness, and chlorine levels.
  

• Balance All Chemicals Simultaneously: When adjusting one chemical level, it can affect the others. Always test and adjust them together.
  

• Clean Pool Filters: Ensure that your pool filter is functioning well. A clean filter ensures proper water circulation, which can help maintain balanced water chemistry.