How to Fix a Green Pool

Swimming pools are a great source of enjoyment and relaxation during hot summer months, but when the water turns green, it can quickly ruin the fun. Green pool water is a common problem that can be caused by a variety of factors, such as poor filtration and circulation free chlorine, pH imbalances, and algae growth. Not only is it unsightly, but it can also be a health hazard if left untreated. If you’re a pool owner, it’s essential to know how to fix and prevent green pool water from happening again.

In this blog post, we will provide a step-by-step guide on how to quickly fix and prevent green swimming pool water. We will cover the main causes of green pool water and explain how to clean your pool with the necessary equipment and chemicals. Additionally, we will provide practical tips for preventing green pool water in the future, including the importance of regular pool maintenance and proper water chemistry. By following our guide, you can enjoy a clean and healthy swimming pool all season long.

(Before and After Heritage Pools Green-to-Clean)

Understanding the Causes of Green Pool Water

Before we dive into how to fix green pool water, it’s essential to understand what causes it in the first place. Green pool water is typically caused by the growth of algae, a microscopic plant that thrives in warm, stagnant water. When the conditions are right, algae can quickly multiply, turning the pool water green, and making it cloudy and unappealing. Poor water chemistry, inadequate filtration and circulation, and lack of proper maintenance are some of the most common causes of algae growth in pools.

Water Chemistry: Maintaining proper water chemistry is crucial to preventing algae growth in your pool. pH is one of the most important factors to keep in check. If the pH is too high or too low, it can create an environment that promotes algae growth. The ideal pH range for pool water is between 7.2 and 7.8. Additionally, chlorine levels should be maintained between 1 and 3 parts per million (ppm) to prevent algae growth.

Filtration and Circulation: A proper filtration and circulation system is essential for keeping your pool water clean and clear. The filter removes debris and contaminants from the water, while the circulation system moves the water through the filter and back into the pool. Without proper filtration and circulation, debris and contaminants can accumulate, providing a breeding ground for algae.

Maintenance: Regular maintenance is key to preventing green pool water. Skimming the surface of the pool regularly, brushing the walls and the pool floor, and vacuuming the debris are all important steps to keep your pool clean. Additionally, shocking the pool with chlorine can kill any existing algae and prevent further growth.

In conclusion, understanding the causes of green pool water is critical to preventing it from happening in the first place. Maintaining proper water chemistry, filtration, and circulation, and regular maintenance are all essential factors to keep your pool water crystal clear and inviting. In the next section, we’ll cover how to clean a green swimming pool once it has already turned dark green again.

How to Clean a Green Pool

If your pool has already turned green, don’t worry; there are steps you can take to fix it. Follow these steps to clean your green pool:

Step 1: Test the Water The first step in cleaning a green pool is to test the water. Use a pool water testing kit to check the pH and chlorine levels. Adjust the pH level to 7.2-7.8 and add chlorine to raise the chlorine level up to 10 ppm.

Step 2: Brush the Walls and Floor Use a pool brush to scrub the walls and floor of your pool to remove any algae growth. This will help break up all the algae, and make it easier to remove.

Step 3: Vacuum the Debris Once you’ve scrubbed the pool walls and floor, use a pool vacuum to remove the debris. You can use a manual vacuum or an automatic pool cleaner to do this. Be sure to clean out the filter regularly during this process.

Step 4: Shock the Pool Shock the pool with chlorine to kill any remaining algae. Follow the instructions on the shock treatment product to ensure you add the correct amount of chlorine for your pool size.

Step 5: Wait and Test Again Allow the shock treatment to circulate for at least 24 hours. Then, test the water again to make sure the pH and chlorine levels of green water are at the correct levels. If needed, adjust the pH level and add more chlorine.

Step 6: Filter and Circulate the Water Run your pool filter for at least 8-12 hours a day, or longer if needed, to help remove any remaining algae and debris. Additionally, make sure your pool pump and circulation system is working correctly to prevent any stagnant water areas that could promote algae growth.

Remember, cleaning a green pool can take time and effort, so be patient and persistent. It’s also essential to address the root causes of algae growth to prevent it from happening again in your future as a pool owner. In the next section, we’ll cover some tips on how to prevent green pool water from occurring.

Preventing Green Pool Water in the Future

Now that you’ve cleaned your green pool, it’s time to take steps to prevent it from happening again in the future. Here are some tips on how to prevent green pool water:

  1. Maintain Proper Water Chemistry: As we mentioned earlier, maintaining proper water chemistry is crucial to preventing algae growth. Test the water regularly, and adjust the pH and chlorine levels as needed to keep them within the ideal range.
  2. Keep Your Filter and Circulation System in Good Condition: Make sure your filter is cleaned regularly and replace it as needed. Additionally, ensure that your pool’s circulation system is working correctly and is adequately sized for your pool.
  3. Skim and Brush Your Pool Regularly: Skim the surface of the pool regularly to remove debris, and use a pool brush to scrub the walls and floor to prevent algae buildup.
  4. Shock Your Pool Regularly: Shocking your pool with chlorine regularly can help prevent algae growth. It’s a good idea to shock your pool at least once a week, or more often if needed.
  5. Use a Pool Cover: Using a pool cover can help prevent debris and contaminants from entering your pool and creating an environment for algae growth.
  6. Consider Using a Pool Cleaner: Using a pool cleaner can help keep your pool clean and clear, especially in hard-to-reach areas. There are many types of pool cleaners available, including manual and automatic options.

By following these tips, you can keep your pool clean and prevent it from turning green in the future. Remember, prevention is key when it comes to maintaining a healthy and enjoyable swimming pool.


A green swimming pool can quickly ruin the fun and relaxation of owning a pool. However, by understanding the causes of green pool algae in water, knowing how to clean it, and taking preventive measures, you can enjoy a clean and healthy swimming pool all season long. Remember to test your water regularly, maintain proper water chemistry, clean your pool’s filter and circulation system, and shock your pool with chlorine regularly. By following these steps, you can prevent algae growth and keep your pool crystal clear.

If you need help cleaning your green pool, consider contacting Heritage Pools, a professional pool cleaning service in Charleston, SC. Our “green to clean” service can quickly transform your green pool into a sparkling, inviting oasis. Don’t let a green pool ruin your summer fun. Contact Heritage Pools today and enjoy a clean, healthy pool all season long.