Pool, Spa & Water Treatment Chemistry worked example

Chemical Dilution at 1.15% target working strength: a worked example

What does the result look like when target working strength reaches 1.15%? The full calculation is worked below with real intermediate numbers. Use it when preparing diluted cleaning, treatment, or test solutions from concentrated stock.

The inputs for this scenario

  • Target working strength: 1.15 % (raised for this scenario; the documented default is 1)
  • Stock chemical strength: 12.5 % (unchanged)
  • Final batch volume: 20 gal (unchanged)

Working through the calculation

  • Applying the documented formula (Concentrate needed = target strength / stock strength x final batch volume) to the inputs above produces each figure below.
  • At this operating point the engine returns 1.84 gal for ratio, the number this scenario is built around.
  • At this operating point the engine returns 0.09 value for raw ratio.
  • At this operating point the engine returns 20 x for efficiency factor.
  • At this operating point the engine returns 12.5 value for stock strength.

How this compares with the baseline

  • Against the tool's baseline example, where target working strength sits at 1% and the headline result is 1.6 gal, this scenario comes in 15% above the baseline at 1.84 gal.
  • A figure at this level is achievable when target working strength is genuinely sustained, not just peaked for a shift. It assumes the stock strength on the label is accurate and current; liquid chlorine degrades and loses several percent strength per month in heat, so verify with a titration for critical dosing.

Results at a glance

  • Ratio: 1.84 gal (headline result)
  • Raw ratio: 0.09 value
  • Efficiency factor: 20 x
  • Stock strength: 12.5 value

Run it with your numbers

  • Every input above is editable in the live Chemical Dilution calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.