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How to Clean an Algae Bloom in a Pool

By Marshal M. Rosenthal ; Updated September 21, 2017

Algae can grow rapidly in a pool and seemingly overnight can turn the water a disgusting green hue. The algae bloom is also smelly -- another reason to get rid of it -- and, most important, it is unhealthy to swim in the pool when algae is present. The algae bloom can be cleaned from the water using supplies available from a pool and spa center or a home and garden shop, along with tools you probably have.

Skim off whatever algae you can from the pool using a pool skimmer. Scrub the inside edges and walls of the pool with an algae brush to dislodge stuck algae.

Purchase sufficient amounts of algaecide, as noted in the instructions on the bag, that match the total gallons of water in the pool.

Turn the pool pump on -- the power switch is located on the electrical control panel that is in the pool shed at one end of the pool. Adjust the speed of the pool pump to maximum -- this involves turning a knob or pressing a switch. Wait 10 minutes before continuing.

Stand at the deep end of the pool. Empty the bag of algaecide into the pool, near the inside edge of the wall, as you walk the perimeter of the pool. Continue this procedure until all of the algaecide has been poured into the pool.

Repeat this procedure, only with the shock treatment powder that was also purchased at the same time as the algaecide, and whose total was determined from the chart on its bag.

Leave the pool alone for 24 hours. The brush the inside edges and walls of the pool with the brush in the same manner as you did earlier. Skim algae off the surface of the water with the pool skimmer. Turn the pool pump off.


Things You Will Need

  • Pool skimmer
  • Pool algae brush
  • Algaecide bags
  • Shock treatment powder bags


  • The gallons of water the pool holds will be specified in the pool manual or can be obtained from the pool manufacturer's website or the contractor who installed the pool.


  • You will need to readjust the pH level of the water, as is done on a regular basis, once the algae bloom has been eliminated.
  • The filter in the pool and in the pool pump assembly should be cleaned afterward to remove any algae that might still be in them.

About the Author


Marshal M. Rosenthal is a technology maven with more than 15 years of editorial experience. A graduate of Brooks Institute of Photography with a Bachelor of Arts in photographic arts, his editorial work has appeared both domestically as well as internationally in publications such as "Home Theater," "Electronic House," "eGear," "Computer and Video Games" and "Digitrends."