Issues/Fixes
Chlorine Lock
A lot of you have heard me use this term lately...
If your pool is in chlorine lock, the best thing you could do is dump it and start with freshwater. #chlorinelock #notyouraveragepoolguy #pooldrain
— Jeremy Knight.
What It Is
Chlorine Lock (Chlorine Inefficiency) A condition where added chlorine becomes ineffective, leaving sanitizer levels low and the water cloudy even after shocking.
How It Shows Up
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Cloudy or dull water
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Low chlorine readings despite adding chlorine
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Algae growth starting even with regular maintenance
How to Fix It
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Partially drain and refill to lower CYA
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Switch to unstabilized chlorine temporarily
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Rebalance water chemistry once CYA is in range
What Causes It
High Cyanuric Acid (Stabilizer) When CYA levels rise above 100 ppm, the stabilizer binds to free chlorine and prevents it from disinfecting properly.
Why It Matters
Chlorine can’t sanitize the water, which leads to unsafe swimming conditions, wasted chemicals, and ongoing water clarity issues.
Prevention
Avoid overusing stabilized chlorine, test CYA regularly, and maintain stabilizer levels within the recommended range to prevent chlorine lock from returning.