Before you use these numbers
Every amount here is a starting point worked out from published charts. Your product's label comes first, and some problems need a pool professional.
Amounts are estimates
They come from your pool size and readings and from published charts. Pool sizes are estimates too, so the calculators start low, give one round at a time, and ask you to retest before adding more. Add some, wait, retest.
The label wins
Products differ in strength and directions. If your product's label gives a different amount, wait or swimming level, follow the label.
When to ask a pool professional
- Green, black or very cloudy water: you can't see the drain at the bottom of the deep end.
- Readings at or beyond the ends of your test's scale, or far outside the normal ranges.
- Hot tubs, and public or commercial pools.
- Anything you're unsure about. The calculators say so whenever a case is outside what the charts cover.
Swimming
This tool cannot tell you the water is safe to swim in. Follow your product label, and if in doubt ask a pool professional.
Your readings
The readings you type stay in this page; the sums run here and aren't sent to us.