Pool CYA Drain and Refill Calculator - Lower Cyanuric Acid
Calculate exactly how much pool water to drain to lower Cyanuric Acid (CYA) levels. Save money and avoid over-draining your pool with this easy stabilizer tool.
Why is High CYA a Problem?
Cyanuric Acid (CYA) is "sunscreen" for chlorine. However, if levels exceed **100 ppm**, it causes "Chlorine Lock." This means your chlorine is present but cannot kill bacteria or algae, leading to a green pool despite high chlorine readings.
Warning: CYA does not evaporate. It only goes up when using "stabilized" chlorine like 3" tablets (Trichlor) or Shock (Dichlor). The only way to lower it is to drain and refill.
Frequently Asked Questions
Does Cyanuric Acid evaporate?
No. Unlike water, CYA stays in your pool. The only way it leaves is through splash-out, backwashing, or physically draining and replacing the water.
Can high CYA damage my pool?
High CYA doesn't directly damage the pool structure, but it makes your chlorine ineffective. This leads to algae growth (Green Pool), which can stain plaster or clog filters.
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