How Much Shock Does Your Pool Need?
"Shocking" means raising free chlorine to a treatment target to oxidize chloramines and address contamination such as algae. The amount depends on your pool volume, the required chlorine increase, and the concentration of the product you are using.
Enter all three inputs above, then choose the shock type to see the dose in pounds, ounces, or gallons. If the pool volume is unknown, use the Pool Volume Calculator first.
Pool Shock Chart (Cal-Hypo, to ~12 ppm)
Rough amounts of 73% cal-hypo shock to take a pool from ~1 ppm up to a 12 ppm shock level:
| Pool Size (gallons) | Cal-Hypo (73%) | 1 lb Bags |
|---|---|---|
| 5,000 | ~0.6 lbs | ~1 |
| 10,000 | ~1.3 lbs | ~1.5 |
| 15,000 | ~1.9 lbs | ~2 |
| 20,000 | ~2.5 lbs | ~2.5 |
| 25,000 | ~3.1 lbs | ~3 |
An algae treatment may require a higher chlorine target, brushing, filtration, and repeat testing. See the green pool guide for the full process.
When to Shock Your Pool
- Weekly to biweekly as routine maintenance during swim season
- After heavy use (a pool party or lots of swimmers)
- After heavy rain or a storm
- When the water looks cloudy or green, or smells strongly of chlorine (that smell is chloramines, not "too much chlorine")
- After opening or before closing for the season
Test free and combined chlorine with a test kit before treatment and again after the required circulation time.