What this tool estimates
Given pool volume (gallons) and a target change in ppm (or a small pH nudge), you can rough out how much of a common balancer or shock you might need. Use the interactive calculator above — then retest.
What you must test first
- Current free chlorine, pH, and alkalinity as relevant
- Approximate volume in gallons
- Product strength on the label (not a generic internet number alone)
How to use the results
Treat any calculator output as a starting point. Add chemical carefully, wait the label’s contact time, retest, and only then decide on a second dose.
Safety disclaimer
Never mix different chlorine products dry or in a bucket. Never pour shock through a skimmer that feeds an automatic chlorinator. Add chemical to water when pre-dissolving, not water to chemical. Gloves and eye protection are not optional.