What is chlorine lock?

"Chlorine lock" is a term used in swimming pool maintenance to describe a situation where chlorine is present in the water, but is not effectively sanitizing the pool. This can happen when the cyanuric acid levels in the pool are too high, which can lead to a buildup of chloramines (combined chlorine) that are not effective in killing bacteria and algae.

Chlorine lock can also occur if the pH levels of the pool are too high or too low, as chlorine works most effectively in a narrow pH range. Additionally, a lack of circulation in the pool or insufficient levels of free chlorine can contribute to chlorine lock.

To resolve chlorine lock, it is important to test the water chemistry and adjust the cyanuric acid, pH, and chlorine levels accordingly. Superchlorination or shock treatments may also be necessary to break down the chloramines and restore the chlorine's effectiveness. Regular maintenance and monitoring of the water chemistry can help prevent chlorine lock from occurring in the future.