Stabilizer (CYA) Calculator
Enter your pool volume and current/target CYA — we'll calculate the dose, or the dilution needed if you're over target.
Result
Safety first
- Never mix chemicals together.
- Always add the chemical to the water — never water to the chemical.
- Wear gloves and eye protection when handling pool/spa chemicals.
- Keep chemicals out of reach of children and pets.
- Always follow the product label — it overrides any guidance here.
Ideal CYA range
30-50 ppm with traditional chlorine; 60-80 ppm for salt pools; 0-30 ppm for hot tubs using chlorine.
Frequently asked questions
What is CYA (cyanuric acid / stabilizer)?
CYA protects chlorine from being broken down by sunlight (UV). Without it, your chlorine would burn off within hours on a sunny day. But too much CYA weakens chlorine's sanitizing power, so it needs to stay within range.
How long does CYA take to dissolve?
CYA dissolves slowly — put it in a sock or your skimmer basket, and retest after about a week once it has fully dissolved.
How do I lower CYA?
The only way to lower CYA is diluting with fresh water (partial drain and refill), or waiting it out with regular backwashing/splash-out over a season.
I use dichlor or trichlor — do I still need to add CYA separately?
No — dichlor and trichlor both add CYA as a side effect every time you use them. Check the Chlorine Calculator to see how much CYA your regular dosing already adds before adding more.