How to Treat Green Pool Water

Test the Pool Water. Use a chemical testing kit to check chlorine and pH levels, as well as assess the severity of the issue. Algae can thrive and turn pool water green when chlorine levels drop below 1 ppm. “Shocking” the water with chemicals is essential to kill the algae and restore the pool to normal chlorine levels.

• Proper pool maintenance, ensuring filters are functional and chlorine and pH levels remain stable, can prevent algae growth from the start.
• Algae will continue to multiply, so if the pool is neglected for even a few days, the water can turn green.

Balance the pool chemicals. Before treating the pool, ensure the pH level is balanced around 7.8 by adding acid or base. This is the ideal range for your pool and is particularly crucial when tackling algae. Here’s how to balance the pH:

• Turn on the pump to circulate the chemicals throughout the pool.
• Adjust the pH level by increasing it with sodium carbonate or decreasing it with sodium bisulfate.

Ensure the filter is functioning efficiently. Clear out leaves, twigs, and debris that might clog the filter. If necessary, backwash the filter and confirm it’s working properly before adding chemicals to kill algae. Set the filter to run 24 hours a day during the cleaning process to remove all dead algae.

Scrub the pool walls and floor. Use a pool-appropriate brush to clean the surfaces before adding chemicals. Algae often cling to pool surfaces, and scrubbing helps remove them while breaking down their structure, allowing chemicals to work faster.

• Pay extra attention to areas with visible algae buildup. Disrupting the algae’s structure ensures a thorough clean.
• Use a nylon brush for vinyl pools, as metal brushes can damage them. Metal brushes are safe for plaster pools.

Shock the pool to treat algae. Use a high dose of chlorine to kill algae and sanitize the pool. Opt for a strong shock product with 70% chlorine content, which is effective against stubborn algae and bacteria. Follow the product instructions to ensure the correct dosage for your pool’s water volume.

• For severe algae infestations, multiple treatments may be necessary to prevent regrowth.
• Shocking the pool will make the water cloudy and dirty initially, but it will clear up as it passes through the filter.

Use an algaecide when chlorine levels are below 5.0. Allow the algaecide to work in the pool for at least 24 hours to effectively eliminate algae.

Regularly clean the filter to remove dead algae and prevent pressure buildup. Once algae die, they settle at the bottom or float in the water, losing their green color.

Vacuum the remaining dead algae from the pool. Brush the pool floor and walls again, then vacuum up the algae debris. If there’s too much dead algae, consider adding a flocculant to clump the algae together, making it easier to vacuum.

Run the filtration system until all algae are completely gone. After treatment, the pool water will gradually clear. If algae reappear, repeat the shock treatment and cleaning process until the algae are fully eradicated.

Recheck chemical levels using a pool testing kit. Ensure all chemical concentrations are within the normal range.

• Use a pool cover daily to prevent leaves and other debris from floating on the surface. This makes it easier to clean up debris before it sinks to the bottom.
• Wear old clothes when handling pool chemicals. Chlorine splashes or spills can bleach fabrics and ruin clothing.
• Take a water sample to your local pool store monthly for computer analysis. This helps detect potential water issues early.
• Maintain chlorine levels between 1.0 and 3.0 ppm to prevent algae from returning.

• Never add chemicals to the pool if you’re unsure of the process. Incorrect chemical use can worsen the situation.
• Exercise extreme caution when handling chlorine. It can cause throat irritation, coughing, or irritate the eyes, skin, and respiratory system.
• Be careful when mixing chemicals with water. Always add chemicals to water, not the other way around.
• Never mix different chemicals together.