Understanding Cyanuric Acid

Understanding Cyanuric Acid


We are moving to a lower cyanuric acid concentration. What does this mean? Stabilized chlorine like the 3” tabs you would usually add to your water contain cyanuric acid (CYA). CYA protects the chlorine from sun degradation and when used and maintained correctly it is a valuable component of your overall pool chemistry. It is however extremely easy to get too much CYA. When too much CYA is added to the pool it becomes overstabilized.

When your pool is over stabilized it can cause costly damage to your plaster and liner, make chlorine less effective, and even be dangerous to swimmers. Over stabilized water increases the risk to swimmers by allowing germs and pathogens to thrive. When water contains more than 50 ppm of CYA, the chlorine is 1/3 as effective as when the CYA is at 20 ppm. So, there is no reason to have a CYA higher than 50. Research has shown that algae count levels can be 35x higher in pools with a CYA of 50 ppm vs. a CYA of 20. (Internal Innovative Water Care)

Not only does CYA level of higher than 50 make chlorine less effective, it also:

  • Degrades plaster surfaces and liner lifespan 
  • Distorts alkalinity readings by 1/3, even when using our advanced spin lab tests
  • Raises the cost of maintaining your pool due to having to drain it and lower CYA 
  • Reduces the Oxidation Reduction Potential more commonly known as REDOX, a measurement that reflects the ability of your chemicals to break down waste products.

All of this means we are lowering our recommended CYA from 50-100 to 20-50 ppm. To do this we will suggest an alternative to traditional chlorine: non-stabilized chlorine, such as Optimight tablets. Optimight is a slow dissolving cal-hypo tabled that can be used in the skimmer or in an Optimight feeder. They provide a high percent of available chlorine without adding stabilizer. These tablets provide oxidation and sanitization without the negative effects caused by the buildup of CYA. 

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