When water turns green due to heat

During a heatwave, the water in your swimming pool turns green and the walls of the pool become slippery. As soon as the water temperature exceeds 28°C, bacteria multiply. Without quick action, green algae will appear. You must react as soon as the water becomes cloudy!

Green pool water

How to treat green water?

Algae growth in your pool causes discoloration of the water, the walls and the bottom of your pool. The appearance of algae implies the proliferation of several types of bacteria and micro-organisms that are dangerous for the health of bathers. Do not swim when the water is green.

  • Maintain a normal pH between 7 and 7.4. Basic water is a favourite playground for algae. They don't like water that is too acidic, but the higher the pH (8 and above), the more likely they will settle in your pool.
  • Check the chlorine level (chlorine acts on the disinfection of the water and fights against the appearance of algae). If you are using stabilized chlorine, it is recommended to maintain its level between 0.7 and 1.2 ppm and if you are using non-stabilized chlorine , it is recommended to maintain a level between 0.4 and 0.7 ppm.
  • Check your filtration system. If the water remains cloudy, you can use a flocculant to make the filtration more efficient. It is advisable to turn it on at night during the heat wave. During the season, remember to clean your filter about once a week.
  • Clean your pool walls and bottom. Use a brush and a broom to scrub the walls (bottoms, water line, stairs,...) to remove the sticky marks.
  • Algaecides use a treatment with algaecide action in case of very turbid water and algae growth.

Protect your pool from the sun

Protect the water as much as possible from UV rays with sunshades, shade sails, etc. to prevent the quality of your pool from deteriorating too quickly. This will slow down the heating of the water and the growth of bacteria and the water will evaporate less quickly.

To conclude, adapt your pool maintenance routine to the weather conditions and protect your pool from the sun.