How to Kill Algae With Chlorine

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Things You'll Need

  • Pool scrub brush

  • Bucket

  • Garden hose

  • Granular chlorine, 2 pounds for every 10,000 gallons of pool water

  • Paint stick

  • Pool vaccuum

Shocking the pool with chlorine helps to kill algae.

Algae like to grow in water environments, which means you can end up with algae in your swimming pool. According to the website Poolcenter, algae spores enter the pool water via the wind, on swimming suits or on the surface of equipment. Once the spores find a home, algae can flourish overnight. All species of algae are one of three colors: green, yellow or black. Shocking the pool with chlorine is one way to kill off algae growth and make the pool safe and clean again.


Step 1

Brush the pool walls to remove any algae buildup.

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Step 2

Fill a bucket 1/2 to 3/4 full with water from a garden hose. You should work as close to the pool as possible to avoid carrying the bucket back and forth. Do the treatment in the evening, and keep everyone out of the pool for at least eight hours; check the chlorine manufacturer's instructions for the exact amount of time people should not use the pool.


Step 3

Pour 1 pound of granular chlorine into the bucket. Always fill the bucket with water and then add the chlorine; do not add the granular product first and then water. Stir the liquid with a paint stick to dissolve the chlorine.

Step 4

Carry the chlorine water to the edge and pour it into the swimming pool. The goal is to disperse it throughout the pool, so move as you pour.


Step 5

Repeat the process, moving around the edge of the pool to cover all sides. The number of buckets depends on the size of your pool. Use 2 pounds of granular chlorine for every 10,000 gallons of pool water. If, for example, you have a 30,000-gallon pool, you need 6 pounds of chlorine.

Step 6

Brush the walls of the pool the next day. Allow the sediment to settle, and then vacuum to remove it.


Step 7

Clean the filter according to the directions for your filter.

Step 8

Rebrush the walls in the evening, and turn the filter on. This should remove any remaining algae.


Following the instructions provided with the algaecide you purchase. Chlorine is just one of many choices to kill algae..

The best way to kill algae is too prevent growth by maintaining proper water chemistry, shocking with chlorine several times a year and testing frequently. Ask a professional for advice if you are unsure of how to treat the pool water.


Pink slime is not algae, according to Pool Manual, but it requires the same shocking treatment.



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