Can't Keep Chlorine Level Up in the Swimming Pool?

So you can't seem to hold a chlorine level in your swimming pool. You keep adding chlorine to the pool only to find that within the next day or two the chlorine reading is back to zero. Your swimming pool is most likely suffering from a condition known as "chlorine lock".

In a nutshell, Chlorine Lock occurs when the level of Cyanuric Acid in the swimming pool gets too high and stops the chlorine from doing its job. Cyanuric Acid is also known as Pool Conditioner or Pool Stabilizer. Ironically, its job is to protect the chlorine from the sun. Without this conditioner, the chlorine will dissipate very quickly leaving the pool unprotected from bacteria and algae. The recommended level of cyanuric acid in a swimming pool ranges from 30 – 80 ppm. Chlorine lock happens when the conditioner level gets too high. As the cyanuric acid level rises above 80 – 100 ppm, the chlorine becomes less and less effective until at some point, it becomes difficult to hold a chlorine reading in the pool for any significant amount of time. Most likely this is what you are experiencing if you keep adding more chlorine only to find when you test for the chlorine level, it is zero again.

If you are having trouble holding the chlorine level in your swimming pool, test the cyanuric acid levels to eliminate this issue. There are Cyanuric Acid Test Strips and Cyanuric Acid Test Kits that are fairly accurate, or you can take a sample of the pool water to your local pool store and ask them if they test for cyanuric acid.

Once you identify that the cyanuric acid level is too high, there is really only one way to solve the problem. The swimming pool needs to be partially drained one or more times until the conditioner level is diluted and the cyanuric acid reading is between 30 – 80 ppm, preferably between 30 - 50 ppm. Once this is accomplished, shock the pool and make sure the filter is clean and your pool maintenance routine should get back to normal!

 

 

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