Algae Growth in Swimming Pools

Types

• Green algae is the most common type of algae found in swimming pools. This algae will float and turn the water hazy and will also collect on the sides and bottom of the pool. A slimy texture to the pool liner is one way to confirm the presence of green algae. Black algae is the most difficult to get rid of and is more common in concrete pools where it can grow into the walls and floor. Scrubbing the dark spots off works temporarily, but those spots will soon return. Yellow algae, also known as mustard algae, forms large sheets in the shady areas of the pool and is more common in areas with long, hot summers.

Causes

• Algae always exists in a pool, but properly balanced chemicals and routine maintenance will keep the growth in check. If the levels of chlorine, bromine and pH are allowed to drop, algae can gain a foothold in the pool. A buildup of old chemicals that are normally eliminated from the pool with shock treatments can also encourage algae growth. Algae can be carried into the pool by the wind and on leaves and other fallen debris; a pool that is not regularly cleaned of this buildup can quickly develop an algae problem.

Eradication

• Balancing the pool's chemistry is the first step in getting rid of algae. Test the water and add chemicals such as chlorine to make sure all the numbers are with within acceptable ranges. Algaecides are available for different kinds of algae, so determine what the pool has been infested with and choose an appropriate algaecide. Some varieties are more resistant than others; yellow and black algae will require a strong chemical. Shocking the pool can also help jump-start the process. Scrub traces of algae from the sides and bottom of the pool to help ensure all the algae molecules are filtered out. Clean the filters regularly to make sure the algae isn't getting recycled back into the pool.

Prevention

• Keeping all the chemicals in balance is key to preventing the growth of algae. The right levels of sanitizing agent will kill algae before the microorganisms begin to multiply. Keeping pH levels in an acceptable range will ensure that all the other chemicals work together properly. Remove any leaves or other debris as soon as they enter the pool, and clean filters regularly. If algae has been a problem in the past, chemicals such as potassium tetraborate can be added to the pool before the problem develops to keep growth in check. Algaestatics are chemicals that are designed to kill algae before it becomes a problem.