Cyanuric Acid Protecting Chlorine from Sunlight

Cyanuric Acid

The chemical that protects chlorine from sunlight destruction is called cyanuric acid. It is also known as conditioner, stabilizer, isocyanuric acid and -s-triazinetrione. The proper chemical mane is cyanuric acid.

  •  protects chlorine from sunlight (UV or ultraviolet) destruction.
  •  slows down the kill time of free chlorine.

Everyone agrees that cyanuric acid protects chlorine from sunlight. And the fact is that cyanuric acid protects chlorine so it stays in the water 6-10 times longer than without it.

Minimum Ideal Maximum
Conditioner 10 ppm 30-50 ppm 150*


Chlorine Lock

For years there have been rumors about “chlorine lock”. The myth says that you can get so much cyanuric acid in the pool that it will lock up all of your chlorine and make it ineffective.

The Maximum Cyanuric Acid  Level

The maximum level allowed in commercial or public swimming pools by most every health department in the U.S. is 100 ppm. There are a few states that allow up to 150 ppm. New York State did not allowed cyanuric to be used at all in any commercial or public pool. Recently, New York changed the code and now allows cyanuric acid to be used in outdoor pools. There are no codes for residential pools.