Algae on my pool

Algae in the water is the main problem that all pool owners want to avoid. It appears in different situations: with the summer heat, during the winter period or in case of a significant increase of the TDS (Total Dissolved Solids). In this article, you will find all our advice on how to effectively combat algae and how to act as soon as the water becomes cloudy.

Algae may appear in the pool water.The water becomes cloudy.

Why do algae grow?

During the wintering period: Algae growth during this period is common, especially if you have practised passive overwintering (total cessation of filtration and treatments) or light filtration during active overwintering.

Une remise en route tardive : As soon as the water temperature reaches 12°, do not delay in de-wintering your pool, even if you will not be able to enjoy your pool for several weeks. The lack of adequate treatment, combined with a rise in temperature and humidity, will inevitably lead to algae. 

Inappropriate chemical treatment: When swimming water is not treated sufficiently or correctly, the pH of the water becomes unbalanced and the disinfectant no longer has sufficient effect. By following ICO's recommendations, you benefit from a continuous analysis of your pool's water quality and from personalised recommendations (adapted to the products you usually use) with precise dosages. 

During the summer months: In hot weather, high water temperatures encourage the growth of algae.

Too high a TDS (Total Dissolved Solids): it can also cause algae growth. It is necessary to measure the TDS level quickly. Find here our video on TDS.

The different algae in the pool water

  • Green algae: these are the most common. The water in the pool becomes green and stains may appear on the bottom and sides of your pool, which will be slippery and slimy to the touch.
  • Black algae: these appear as black, slimy spots. They are found on the walls and bottom of pools as well as on the joints of the tiles if your pool has this type of coating.
  • Mustard algae: as their name suggests, they have a yellowish colour and also settle on the bottom and walls of your pool. However, unlike other algae, they are easy to remove and prefer shady areas to grow.
  • Pink / red algae: red or bright pink in colour, these algae generally grow on plastic coatings. They are therefore found on skimmer baskets, cleaners, sealed parts, ... .

How to prevent limescale?

  • Maintain a normal pH between 7 and 7.4. Basic water is a favourite playground for algae. The higher the pH (8 and above), the more likely they are to 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. During the season, remember to clean it regularly, about once a week. In hot weather, it is advisable to turn on the filtration system at night. 
  • Clean your pool walls and bottom regularly.

How do I remove algae from my pool?

Algae growth in your pool causes deposits on the walls and bottom of your pool. The appearance of algae means the presence of several types of bacteria, some of which are dangerous for the health of bathers. It is therefore essential to intervene quickly to preserve your equipment and protect your health. But, the development of algae in your pool will no longer be a chore now that you know how to react to their appearance.