calcs.homes
calcs.homes
Cyanuric acid (stabilizer or conditioner) protects chlorine from UV breakdown. Enter your current and target level to find how much to add.
Estimate only — stabilizer dissolves slowly; add to the skimmer or a sock, and retest after a few days.
We take the difference between your target and current CYA reading, multiply by your pool's volume in 10,000-gallon units, then multiply by 1.3 oz — the amount of cyanuric acid that raises stabilizer by 1 ppm per 10,000 gallons. A 15,000-gallon pool going from 0 to 40 ppm, for example, needs roughly 78 oz (about 4.9 lb) of conditioner.
Unlike chlorine or pH, cyanuric acid doesn't break down under UV or through normal sanitizer use — it only leaves a pool through splash-out, backwashing, or draining — so this dosing step is typically a one-time or once-a-season addition rather than part of a regular routine. The 30-50 ppm target range balances protecting chlorine from sunlight against reduced sanitizer effectiveness at high CYA levels (chlorine lock), which is why hitting the right number matters more than just adding more.
30-50 ppm for pools using chlorine as the primary sanitizer. Too little and chlorine burns off quickly in sunlight; too much and chlorine becomes less effective (chlorine lock).
Stabilized chlorine products (like trichlor tablets) add cyanuric acid every time you use them. If CYA keeps climbing, switch to unstabilized liquid chlorine or partially drain and refill to dilute it.