Stabilizer calculator

Stabilizer is cyanuric acid: 1 lb raises 10,000 gallons by about 12 ppm. It shields chlorine from the sun, so an outdoor pool needs some.

It never breaks down or evaporates — it only leaves with drained water. So add it slowly and never overshoot.

The product label always wins — if it says something different, follow the label.

About 30–50 ppm for a chlorine pool and 60–80 for a salt pool. Hot tubs need little or none.

Chlorine tablets (trichlor) and dichlor add stabilizer every time you use them.