Cyanuric Acid (Stabilizer) Calculator
Enter your pool volume and current and target cyanuric acid to get exactly how much stabilizer to add, in ounces and pounds. Works for both chlorine and saltwater pools.
Stabilizer to add to raise CYA by 40 ppm
80.1 oz
about 5.01 lb
of cyanuric acid (pure stabilizer)
Most chlorine pools aim for 30 to 50 ppm CYA; saltwater pools usually want 60 to 80. Granular cyanuric acid dissolves slowly, so add it in a sock in the skimmer basket or the pump basket, run the pump, and do not backwash for 24 to 48 hours while it dissolves. Retest after a few days. If you use dichlor or trichlor tablets, those raise CYA on their own, so test before adding more.
Stabilizer sets your chlorine target
Cyanuric acid is the most misunderstood number in pool care. It shields chlorine from the sun, which is why an outdoor pool needs some, but too much weakens the chlorine you have and forces you to run a higher free chlorine level to stay sanitary. Get CYA into range first, then set your chlorine from it with the chlorine calculator. As always, start from an accurate pool volume.
Frequently asked questions
How much cyanuric acid do I add?
It depends on your volume and how far CYA needs to rise. Roughly 13 ounces of cyanuric acid raises 10,000 gallons by about 10 ppm. This calculator scales that to your exact volume and target and shows the result in ounces and pounds.
What CYA level should my pool be?
Most traditional chlorine pools target 30 to 50 ppm. Saltwater pools with a salt chlorine generator usually want a higher range, around 60 to 80 ppm, because it protects chlorine from sunlight in an outdoor pool that generates it slowly.
How do I add cyanuric acid?
Granular stabilizer dissolves slowly. Put it in a sock in the skimmer or pump basket, run the pump to circulate, and do not backwash the filter for 24 to 48 hours while it dissolves. Retest after a few days, since an early test will read low before it has fully dissolved.
How do I lower cyanuric acid?
You cannot remove CYA with chemicals. The only reliable way to lower it is to drain part of the pool and refill with fresh water. Rain and splash-out also dilute it slowly over time.
Why is my CYA rising on its own?
Dichlor granular shock and trichlor tablets both contain cyanuric acid and add it every time you use them. If you chlorinate with those, your CYA climbs over the season, which is why many people switch to liquid chlorine once CYA is in range.
Dosing based on the standard mass balance for a direct weight-to-ppm solid (about 13 oz per 10 ppm per 10,000 gallons), consistent with Trouble Free Pool and other established pool-chemistry references. Follow your product label and retest after it dissolves.