Pool Stabiliser Calculator Australia
Work out how much cyanuric acid (CYA) to add to an outdoor chlorine pool. Dose from a reliable test, add in stages, and stop before stabiliser makes chlorine less effective.
Use your actual pool readingsOpen the calculator for a dose based on pool type, volume, and current test result.What CYA level should you target?
- For outdoor chlorine pools, 30 ppm is a practical starting target; Queensland guidance says ideally 30 ppm or less and no more than 50 ppm.
- CYA protects free chlorine from Australian UV, but excess CYA slows disinfection and is normally reduced by dilution.
- Do not use CYA in indoor pools, spas, bromine pools, or Naked freshwater systems.
Australian dose chart
For near-pure stabiliser, grams required ≈ pool litres × desired ppm increase ÷ 1,000. Check product concentration and label directions before dosing.
| Pool volume | Raise CYA by 10 ppm | Raise CYA by 20 ppm |
|---|---|---|
| 30,000 L | 300 g | 600 g |
| 50,000 L | 500 g | 1.0 kg |
| 75,000 L | 750 g | 1.5 kg |
| 100,000 L | 1.0 kg | 2.0 kg |
How to dose without overshooting
- Test CYA with a suitable kit; do not calculate from how much product was previously added.
- Subtract the current reading from the target. If already near 50 ppm, do not add more.
- Calculate the dose, then follow the product label—many products are added through a skimmer sock or dissolved gradually.
- Run circulation and allow the product’s stated mixing time before retesting.
- Avoid topping up with stabilised chlorine once CYA is near its upper limit.
Safety and system checks
- Never mix pool chemicals or add water to concentrated chemicals.
- CYA is lost mainly through water replacement, splash-out, or backwashing; high readings generally require partial drain and refill.
- Follow your sanitiser and pool-surface manufacturer when its target is narrower.