Water Treatment Dosing

Work out how much chlorine or coagulant to add to a known volume of water. Choose the tab for the chemical you're dosing, enter the volume and the target dose, and the tool converts it into a real product mass.

What to enter

• Tab: Chlorine dose or Coagulant.
• Water volume: the batch volume in m³.
• Chlorine demand (chlorine tab), the chlorine consumed by the water before any residual is left, in mg/L.
• Target residual (chlorine tab), the free chlorine you want remaining, typically 0.2–0.5 mg/L.
• Product (chlorine tab), which chlorine source you'll dose; the tool corrects for its available-chlorine strength (e.g. 12.5% sodium hypochlorite).
• Coagulant + Jar-test dose (coagulant tab), the coagulant type and the dose your jar test found, in mg/L.

Reading the result

The headline is the active chemical mass needed (kg of Cl₂ or coagulant). For chlorine you also get the product mass after correcting for strength, plus the applied dose. The working formula is shown so you can check it.

Worked example

For 100 m³ with 1.5 mg/L demand and a 0.3 mg/L residual, the applied dose is 1.8 mg/L → 0.18 kg of Cl₂, which as 12.5% sodium hypochlorite is about 1.44 kg of product.