How to Get Rid of Green Pool Water

Enjoy clear water with a balanced pool.

Green pool water is caused by algae. Algae spores constantly enter the pool from the wind, rain or contaminated equipment. When sunlight, warm temperatures and carbon dioxide become abundant, algae can seemingly explode overnight. Algae flourishes in pools with unbalanced water -- usually when chlorine levels fall below 1 ppm (parts per million). To clear up the water and remove the algae you will need to restore your pool to the right pH and chlorine levels.

Things You'll Need

• pH test strips
• Chlorine test strips
• Soda ash
• Muriatic acid
• Brush
• Chlorine
• Algaecide
• Pool vacuum

Instructions

1. Check the pH of your pool with pH pool test strips. Compare the reading on the test strip with the provided pH chart.

2. Raise your pH with soda ash or lower the pH with muriatic acid to restore your pool's pH to between 7.2 and 7.8. Follow the directions of your pool chemicals to see how much to add or reference the chart in the resources below.

3. Brush the walls and floor of your pool to suspend the algae in the water. Algae that is stuck on the wall or sitting on the floor of the pool will be hard to penetrate and kill.

4. Add chlorine to your pool to bring the concentration up to 10 ppm for slightly green water. Bring it up to 25 ppm for water that is almost solid green.

5. Allow the pool pump to filter that water for 12 to 24 hours and periodically remove the filter cartridge to remove filtered algae material.

6. Add algaecide at the recommended level when the chlorine concentration falls below 5 ppm. Brush the pool again to dislodge any algae that has re-adhered to the wall or floor of the pool.

7. Vacuum all of the dead algae from the bottom of the pool once it settles. Re-balance the pH and chlorine levels of the pool to the optimum levels for swimming and enjoy your algae-free pool.

Tips & Warnings

• Some pool covers block sunlight from penetrating the water of the pool. If sunlight cannot penetrate into your pool, algae will not be able to grow. Consider using a pool cover that blocks sunlight if you have persistent algae problems.

References

• Poolcenter.com: Algae
• Swimming Pool Designs: What Causes Green Pool Water And How To Fix It

Resources

• North Carolina Division of Environmental Health: Water Chemistry for Swimming Pools