How to Treat Pool Algae

Water balance, which means the correct pH, alkalinity and calcium hardness levels, is critical in the fight against algae. Although these water properties themselves cannot kill the algae, levels in the proper range provide the working medium needed for chlorine to function and kill the algae. Low pH, for example, equals ineffectual chlorine, which can translate into a green nightmare for the pool owner. Algae needs to be dealt with quickly and removed once it appears. Weekly prevention during the season is required for a healthy pool.

Things You'll Need

• 8- to 16-foot extension pole
• Leaf net attachment
• 18-inch curved wall brush attachment
• Vacuum system
• Pool water test kit
• Alkalinity increaser
• pH plus
• pH minus
• Calcium hardness increaser
• 3-inch chlorine pucks
• Chlorine shock 65 percent concentration
• Algicide 60 percent concentration

Instructions

1. Remove all leaves and debris from the pool surface and pool bottom with the extension pole and leaf attachment. Empty the skimmer and pump baskets. This removes food sources for algae, such as decaying leaves.

2. Empty the pool, then brush the entire service with the extension pole and curved wall brush attachment. Every inch of the sides and bottom must be brushed. Algae must be removed from the surfaces, or when treatment is applied, only the outer layers will be killed, leaving lower layers protected.

3. Vacuum the entire pool, which will remove all of the fine material that may have accumulated on the bottom. Refill to the proper level and test the water for pH, alkalinity and calcium hardness levels. Complete the process by adding any of the balancing chemicals required based on the test results--pH should be 7.2 to 7.6, alkalinity should be between 80 and 120 parts per million and calcium hardness should be between 150 to 240 parts per million.

4. Shock any existing algae with a double dose of chlorine shock and do not permit swimming until this super dose of chlorine dissipates, probably by the next day.

5. Pour in the recommended dosage of algicide immediately after the double dose of shock is applied. If algae is very heavy, add more algicide using judgment in proportioning equal to the threat. The addition of both the shock and the algicide should have an immediate effect on the algae, and a white foamy substance will be like froth on the pool surface. This is the dead algae, which can be scooped off with the net.

6. Prepare to backwash the filter if the water pressure on the valve rises between 6 to 10 pounds per square inch higher than when the process began. The dead algae can accumulate in the filter canister and make it harder for the water to flow, which is why the pressure increases. Backwash and continue to filter the pool normally. Add more shock and algicide if the algae is persistent or returns.

Tips & Warnings

• Add a weekly maintenance dose of algicide to the pool throughout the entire swim season as a preventative and precautionary measure.

References

• Pool Manual