How to Diagnose Chlorine Lock in a Swimming Pool

While swimming pool chemicals help maintain the quality of your water, they occasionally contribute to problems. Chlorine lock results when insufficient water replacement allows the build-up of cyanuric acid (CYA), often called a stabilizer. When chlorine lock occurs, the swimming pool chemicals lose their ability to work as they should.

Difficulty: Moderately Easy

Instructions

1. Monitor the clarity of the water in your swimming pool. Many swimming pool problems occur while the water looks crystal clear. With chlorine lock, you may see hazy water or a build-up of algae or other organic material.

2. Test the pH levels in your swimming pool on a regular basis. Swimming pool chemicals affect the pH levels which dictate the entire chemical balance for your swimming pool. A high pH level indicates slowed or ineffective chlorine and the possibility of chlorine lock.

3. Lower the pH level. The addition of muriatic acid or sodium bisulfate to your swimming pool normally lowers the pH level. You should perform an acid demand test before adding any swimming pool chemicals to the water. Remember to add the acid to the water in the correct amount.

4. Evaluate the levels of chlorine in your swimming pool. Free chlorine has not bonded to anything in the water and may react with substance to disinfect the pool. Combined chlorine already bonded to a substance. The total chlorine residual equals the amount of free chlorine plus the amount of combined chlorine.

Tips & Warnings

• Many swimming pool experts and professional swimming pool cleaning companies consider chlorine lock a myth.