Pool, Spa & Water Treatment Chemistry worked example

Oxidizer Demand with estimated contaminant load of 130 bather-hours or units: a worked example

This scenario runs the oxidizer demand calculation on the strong side: estimated contaminant load of 130 bather-hours or units, with every other input held at its documented default. Use it after heavy bather load, storms, fecal events, algae cleanup, or combined chlorine issues.

The inputs for this scenario

  • Estimated contaminant load: 130 bather-hours or units (raised for this scenario; the documented default is 50)
  • Oxidizer demand factor: 0.08 ppm / unit (unchanged)
  • Treatment efficiency correction: 1.11 x (unchanged)
  • Safety buffer factor: 1 x (unchanged)

Working through the calculation

  • Applying the documented formula (Oxidizer demand = contaminant load x demand factor x efficiency correction x safety buffer) to the inputs above produces each figure below.
  • At this operating point the engine returns 11.54 ppm for oxidizer demand, the number this scenario is built around.
  • At this operating point the engine returns 11.54 value for base product.
  • At this operating point the engine returns 1 x for multiplier.
  • At this operating point the engine returns 10.4 value for factor a x b.

How this compares with the baseline

  • Against the tool's baseline example, where estimated contaminant load sits at 50 bather-hours or units and the headline result is 4.44 ppm, this scenario comes in 160% above the baseline at 11.54 ppm.
  • Use it before shocking after a high-bather-load event, a storm, or an algae or chloramine problem, when you need a defensible dose target instead of a habit dose. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Oxidizer demand: 11.54 ppm (headline result)
  • Base product: 11.54 value
  • Multiplier: 1 x
  • Factor A x B: 10.4 value

Run it with your numbers

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

Last reviewed 2026-05-12.