Why do swimming pools turn green?


Why do they turn green so quickly once you stop dumping chemicals into them?

In: Biology

Algae grows. Little water organisms like plants. The chemicals keep them from growing in the stagnant water. Once the chemicals break down its like a perfect home for them. Sun, stagnant water, nothing to eat it. So it grows out of control.

Chlorine is used to usually keep things sanitary. Chlorine also breaks down quickly in heat and sunlight. Once water doesn’t have enough chlorine to deter the growth of algae, it can easily multiply day after day as it feeds on sunlight as it is a chlorophyll based single cell lifeform.

Algaecide is also commonly used is another family of chemicals that keep algae from growing and are toxic to algae.

Algae also feeds on phosphates, so excessive phosphates in the water chemistry will make populations explode once the chlorine is gone, just like fertilizer for a plant (which phosphates are).