Cyanuric acid

Cyanuric acid is a chemical that is added to dichlor and trichlor pool products to help stabalise the chlorine in outdoor swimming pools. Cyanuric acid forms a weak bond with free chlorine in the pool water, protecting it from the sun’s ultraviolet rays to reduce chlorine loss. If levels of cyanuric are too low then the free chlorine is quickly destroyed by the sun’s UV. If the levels of cyanuric are too high then the effectiveness of the free chlorine is reduced and it becomes and ineffective sanitiser for your pool. The time it takes to kill bacteria in the water is longer and the chlorine is less effective in keeping the water clean and problems such as increased cloudiness and exceeding combined chlorine limits can occur.
Ask your pool company what the level of cyanuric acid is in your pool and how they test for it? It should be done on a weekly basis and adjusted accordingly.