Why is my pool cloudy/green?

AIS chlorinators automatically adjust to your pool’s water composition to deliver the correct dosage of chlorine to your pool.  In the case of a cloudy or green pool additional factors may be impacting on chlorine levels. The most likely cause of a cloudy/green pool is low chlorine levels. Low chlorine levels can be caused by:

  • Insufficient salt in the pool – preventing the chlorinator from generating enough chlorine.
  • Insufficient chlorinator running time – AIS recommends running your filtration system for at least eight hours during Summer; six hours during Autumn and Spring and four hours during Winter (in Australia).
  • Chemical or pH imbalance – a chlorine stabiliser (such as cyanuric acid*) should be used in conjunction with any chlorinator. Talk to your professional pool care consultant to find out more.
  • Chlorinator cell needs cleaning – the chlorinator cell must be regularly cleaned to prevent calcium build up. Follow AIS’ instructions regarding how to clean your cell.
  • Black spot algae bloom – black spot often grows in areas of poor water circulation such as corners and steps. Black spot algae consumes chlorine quickly and a dosage of acid or chlorine may be required to rectify the issue.  Talk to your professional pool care consultant to find out more.
  • Breakdown or malfunction of chlorinator – regularly check your chlorinator to ensure it is working.

NB: it may be necessary to shock dose your pool using liquid chlorine to solve the problem of cloudy or green pools. Talk to your professional pool care consultant about the right approach for your pool.

*Stabiliser, or cyanuric acid, is a compound which protects the chlorine from the negative effects of UV and heat. It ensures that pool water remains clean and clear and also reduces the amount of chlorine needed to maintain disinfection.

According to AIS’ research results, pools without stabiliser can lose about 90% of their total chlorine residual in less than three hours on a sunny day. Under the same conditions however pools treated with 25 to 50 milligrams of cyanuric acid per litre of pool water only lose only 10% to 15% total chlorine.

Ideally, stabiliser should be maintained at a level of about 50 ppm with the recommended limits being 30-50 ppm.

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