Last Updated: February 15, 2023

Why Is My Pool Water Green?

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If your pool water is green, you have an algae problem. While algae itself is not dangerous to your health, it promotes growth of bacteria and other microorganisms. Left unattended, algae can also clog your filter and damage the surface of the pool.

Algae is easily treatable my cleaning the pool and “shocking” it with chlorine or your salt chlorinator system. Depending on the severity of the problem, you might have to shock it more than once. You can do the work yourself if you’re willing to invest the time, or you can hire a pool service.

How Do I Get Rid of Green Swimming Pool Water?

Here’s a step-by-step guide to removing algae:

  • Clean the walls and floor of the swimming pool with a pool brush to remove algae. This step is important because it will make the shock treatment more effective.
  • Test the water for proper pH balance - between 7.2 and 7.6. If the pH levels are off, the chlorine treatment will not be as effective.
  • Consult the manufacturer’s instructions to find out how much chlorine shock to add. The amount also depends on the severity of the problem. Adding shock is best done at dusk or after because the sun can burn off the chlorine. Always dissolve the shock in a bucket of water before adding it to the pool water, and make sure the filter is running.
  • Wait at least a day to see if conditions have improved. If not, repeat the shock treatment.
  • When the pool no longer looks green, vacuum the pool to remove the dead algae, which will have taken on a white or grayish color. Clean and wash the filter, too.
  • Test the pH balance again and all chemical levels. Adjust as needed.
  • To prevent algae from returning, consider regular treatments with algaecide.

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Green Pool Water

Hiring a Professional

Hiring a professional pool service to treat your algae problem usually costs anywhere from $250 to $500, but the price can run higher if the problem is stubborn or severe. Algae removal and prevention are not including in regular pool maintenance packages. Black algae is especially difficult to remove, so budget north of $500 for that.

The chemicals to treat algae usually run about $50 to $100.

Once the pool is clean, you might want to consider investing in an ionization system to prevent regrowth. You can find a good one for $200 to $300.

Find the Best Swimming Pool Pros Who Will Compete for Your Business

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Try Our Free Pool Cleaner Cost Calculator

Fill out our 30 second free form to receive competitive pricing from pre-screened pool companies. No commitments. Our service is always free!