Algae is a plant that can grow in the swimming pool water. It is the most common swimming pool problem and it gives rise to other problems, like making the surface slippery and blocking the filters installed in the pool. The growth of algae can lead to black spots at the base of the swimming pool and make the swimming pool water dark green or cloudy.

Possible reasons:

Inadequate level of chlorine in the water.

Improper pool maintenance.

Solutions:

Use chlorine in adequate quantities.

Brush the parts of pool where algae is present.

Use of algaecide is also recommended.

Prevention:

Maintain a proper level of chlorine (3 ppm) in the pool water.

A mixture of chlorine and algaecide is recommended, if algae is a recurrent problem.