You tested the water. Here's exactly what to add.
Pick the number that's off. Get the amount in pounds and ounces of the product in your shed, for your pool's gallons. No sign-up, works with wet hands.
- Free chlorineLow, or zero after a storm
- pHToo high or too low
- AlkalinitypH keeps drifting
- Stabilizer (CYA)Chlorine burns off fast
- SaltSalt cell says low
- ShockGreen, cloudy or smelly
Don't know your gallons? Start with the pool size calculator.
All calculators
Free, no account.
- Pool Volume CalculatorHow many gallons your pool holds, for rectangle, round, oval and kidney pools.
- Pool Chlorine CalculatorHow much liquid chlorine, bleach, cal-hypo, dichlor or trichlor to raise your free chlorine.
- Pool Shock CalculatorHow much shock to add to break down combined chlorine (the chlorine smell and cloudy water).
- Pool Salt CalculatorHow many pounds and 40-lb bags of salt to reach your salt cell's target level.
- Pool pH CalculatorHow much soda ash to raise pH, or muriatic acid or dry acid to lower it.
- Pool Alkalinity CalculatorHow much baking soda to raise total alkalinity, or acid to lower it.
- Pool Stabilizer CalculatorHow much stabilizer (cyanuric acid, CYA) to add, or how much water to drain if it's too high.
- Hot Tub Chemical CalculatorChlorine, pH and alkalinity amounts sized for a hot tub's small volume.
How we check the numbers
Every formula on this site is checked against at least two published references, like manufacturer technical data and university extension guides. Each calculator shows its math and lists those sources, so you can check it yourself.