Pool, Spa & Water Treatment Chemistry worked example

Chemical Feed Pump Setting with required treatment dose of 5 mg / L: a worked example

What does the result look like when required treatment dose reaches 5 mg / L? The full calculation is worked below with real intermediate numbers. Use it to set metering pumps for sanitizer, acid, caustic, coagulant, or specialty treatment feeds.

The inputs for this scenario

  • Required treatment dose: 5 mg / L (raised for this scenario; the documented default is 2)
  • Feed solution concentration: 100 mg / mL (unchanged)
  • Treated water flow: 227 L / min (unchanged)

Working through the calculation

  • Applying the documented formula (Feed pump setting = required dose / feed solution concentration x treated water flow in L/min) to the inputs above produces each figure below.
  • At this operating point the engine returns 11.35 mL / min for ratio, the number this scenario is built around.
  • At this operating point the engine returns 0.05 value for raw ratio.
  • At this operating point the engine returns 227 x for flow rate (l/min).
  • At this operating point the engine returns 100 value for stock concentration (mg/ml).

How this compares with the baseline

  • Against the tool's baseline example, where required treatment dose sits at 2 mg / L and the headline result is 4.54 mL / min, this scenario comes in 150% above the baseline at 11.35 mL / min.
  • A figure at this level is achievable when required treatment dose is genuinely sustained, not just peaked for a shift. It assumes a steady water flow and a stable feed solution strength; degraded chlorine or a fluctuating flow will drift the actual dose, so confirm with a residual test.

Results at a glance

  • Ratio: 11.35 mL / min (headline result)
  • Raw ratio: 0.05 value
  • Flow rate (L/min): 227 x
  • Stock concentration (mg/mL): 100 value

Run it with your numbers

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

Last reviewed 2026-05-12.