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Prevent and Treat Algae

Prevent and Treat Algae

Algae are microscopic plants that enter your pool by rain, wind and fill water. If allowed to grow unchecked, your water will quickly become unusable. Algae prevention and treatment is vital to effective and efficient pool care.


Causes of Algae Growth

Algae growth is usually caused by one of the following conditions:


Inadequate, Free, Available Chlorine Levels

Free, available chlorine levels can be depleted quickly by heavy rains, high-bather loads or poor maintenance procedures. Check free, available chlorine levels frequently during such conditions. Add a sanitizer as needed, according to label instructions.


High pH

Alkaline water prevents chlorine from effectively killing algae. Use a pH decreaser, as directed on the label, to lower the pH to the correct level of 7.2 to 7.6.


Dirty Pool Surfaces

Dirt and slime accumulation on pool surfaces provides the perfect location for algae problems to start. Brush and vacuum weekly to eliminate this source of trouble.



Types and Symptoms of Algae Growth

Hazy or cloudy water, green water, visible algae growth or an inability to maintain a proper chlorine level are signs that algae could be growing in a pool. Take steps to treat the problem before it makes the pool unusable. There are varieties of algae that can grow in swimming pool water.

Green Algae: The most common type of algae and also the easiest to prevent or eliminate. Green algae are free-floating or surface-clinging and can turn a pool green in a matter of hours.

Black Algae: A filamentous growth on the rough surfaces of the pool. It appears as black, slippery spots on pool surfaces, and it also forms a protective coating. Black algae are typically found in plaster or gunite pools.

Mustard Algae: Appears as orange, yellow or mustard spots on pool walls and floors. It often forms on the shaded side of the pool in all pool types. It's easy to brush off but difficult to eliminate.



Prevent and Treat Green Algae


Step 1

Check filtration and circulation systems for malfunctions.


Step 2

Check the pH and adjust, if necessary, to 7.2 to 7.6.


Step 3

Add algaecide; follow label directions. Allow it to work overnight. Then brush and vacuum pool surfaces. Backwash the filter to remove accumulations of dead algae and debris.


Step 4

Treat a second time if the pool is experiencing a major infestation.


Step 5

Return to normal maintenance with chlorinating products, shocks and balancers.


Step 6

Add an algaecide according to the label directions for preventive maintenance.



Prevent and Treat Black Algae


Step 1

Check the pH and adjust, if necessary, to 7.2 to 7.6.


Step 2

Vigorously brush away any visible algae.


Step 3

Vacuum pool surfaces and backwash to remove as much debris as possible.


Step 4

Add a chlorinating shock product; follow label directions.


Step 5

Add an algaecide that will treat black algae for all pool types. Allow it to work overnight. Then brush and vacuum pool surfaces. Backwash the filter to remove accumulations of dead algae and debris.


Step 6

Treat a second time if the pool is experiencing a major infestation.


Step 7

Return to normal maintenance with chlorinating products, shocks and balancers.


Step 8

Add an algaecide according to label directions for preventive maintenance.



Prevent and Treat Mustard Algae


Step 1

Check the pH and adjust, if necessary, to 7.2 to 7.6.


Step 2

Brush and vacuum pool surfaces.


Step 3

Backwash the filter to remove accumulations of dead algae and debris.


Step 4

Add a chlorinating shock; follow label directions.


Step 5

Add an algae treatment product suitable for mustard algae; follow label directions.


Step 6

Treat a second time if the pool is experiencing a major infestation.


Step 7

Return to normal maintenance with chlorinating products, shocks and balancers.


Step 8

Add an algaecide according to label directions for preventive maintenance.