How to Remove Green Algae From Pool Water

Green algae is one of the most common issues pool owners face. It grows quickly, making your pool water murky and slippery while creating an unsafe swimming environment. Understanding the impact of algae helps you see why prompt removal is necessary.

Risks of Letting Algae Spread

• Water becomes cloudy and unattractive

• Surfaces become slippery, increasing the risk of falls

• Algae clogs filters and equipment

• Bacteria can thrive in algae-rich water

Tools and Supplies You Will Need

To tackle green algae effectively, prepare the right tools and chemicals in advance.

Basic Supplies

• Pool shock (calcium hypochlorite or similar)

• Algaecide

• Pool brush with stiff bristles

• Skimmer net

• Test strips or liquid test kit

• Pool vacuum

• Safety goggles and gloves

Optional Extras

• Clarifier to help water clear faster

• Extra filter cartridges if your filter gets overloaded

Step-by-Step Guide to Removing Green Algae

Follow this process to eliminate green algae and restore your pool water.

Step 1: Test the Water Chemistry

• Use test strips or a test kit to check chlorine, pH, and alkalinity.

• Adjust pH to around 7.2–7.4 for optimal chlorine effectiveness.

• Make sure the chlorine level is adequate before proceeding.

Step 2: Remove Debris

• Skim the water surface to remove leaves, bugs, and visible algae clumps.

• Vacuum debris from the pool floor.

• Clean the skimmer and pump baskets.

Step 3: Brush Pool Walls and Floor

• Use a stiff-bristled brush to scrub walls, steps, and corners.

• Pay special attention to shady areas where algae thrive.

• Brush loose algae toward the main drain to aid in removal.

Step 4: Shock the Pool

• Follow the package directions to add pool shock at night.

• For heavy infestations, use a double or triple dose of shock.

• Run the pump continuously for 24 hours after shocking.

Step 5: Add Algaecide

• After shocking, add an algaecide to prevent regrowth.

• Choose an algaecide labeled specifically for green algae.

• Follow the recommended dosage carefully.

Step 6: Run the Filtration System

• Run your pump and filter nonstop for at least 24–48 hours.

• Monitor the filter pressure and backwash or clean the filter as needed.

• Keep circulating the water to clear out dead algae.

Advanced Tips for Stubborn Algae

Persistent Algae Spots

• Use a pool brush daily to keep algae from reattaching.

• Spot-treat with algaecide directly on problem areas.

Filter Maintenance

• Check and clean your filter more frequently during this process.

• Consider replacing the filter media if it is old or heavily clogged.

Preventing Green Algae in the Future

Once you clear your pool of green algae, ongoing maintenance is key to preventing it from returning.

Regular Maintenance Habits

• Test and adjust water chemistry at least twice a week.

• Keep chlorine levels within the recommended range.

• Brush and vacuum your pool weekly.

• Run the pump long enough each day to fully circulate water.

Seasonal Considerations

• During hot or rainy weather, test more often as conditions can promote algae growth.

• After pool parties or heavy use, shock the pool to restore sanitizer levels.

Safety Tips While Treating Algae

• Always wear gloves and goggles when handling chemicals.

• Keep chemicals out of reach of children and pets.

• Avoid swimming until chlorine and pH levels return to safe ranges.

• Store chemicals in a cool, dry place away from direct sunlight.

Helpful Notes on Water Clarity

• Even after killing the algae, water may remain cloudy for a day or two.

• Use a clarifier to speed up the clearing process.

• Keep the filter running and clean it regularly during this phase.

By following these detailed steps and tips, you can successfully remove green algae from your pool and keep it sparkling clean and safe for swimming throughout the season.