UV Chlorine Degradation & Loss Calculator
Calculate how much chlorine you lose to sunlight UV rays. See how Cyanuric Acid (CYA) stabilizes and protects your pool's free chlorine levels.
The "Sunscreen" for Chlorine
Cyanuric Acid (CYA) is often called **stabilizer** or pool sunscreen. Without it, the sunะฒะโขs ultra-violet (UV) rays can destroy **90% of your chlorine** in just two hours. CYA physically protects the chlorine molecule from being torn apart by photons, making it last through the hot afternoon.
Pro Tip: Ideal CYA is 30-50 ppm for chlorine pools and 70-80 ppm for saltwater pools. Too much CYA (over 100) will "lock" the chlorine, making it ineffective.
Frequently Asked Questions
Can I have zero CYA?
Only in indoor pools or hot tubs protected by a lid. In an outdoor pool, zero CYA means your chlorine will be gone by noon, even if you add a double dose in the morning.
Does cloudy weather stop UV loss?
No. UV rays penetrate clouds quite effectively. You might lose 20-30% less than a full sun day, but the degradation is still significant without stabilizer.
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