Polymer Flocculant Dose Calculator

Polymer is dosed as active product but bought as a formulation. Enter flow, jar-test dose, and the product’s active content to get product lb/day — and gal/day if you give the liquid density.

Water flow

Flow unit

Jar-test dose (mg/L active polymer)Dose of active polymer, not of product.

Product active content (%)Emulsion products are often 25–50% active; dry powder about 90%+.

Liquid density (lb/gal)Leave blank for dry product. Typical emulsion: about 8.6–8.8 lb/gal.

Density is only needed for the gal/day result.

Polymer Feed Rate

Item	Value

How the calculation works

Formulas
Flow (MGD) = gpm × 1,440 ÷ 1,000,000
Active polymer (lb/day) = 8.34 × flow (MGD) × dose (mg/L active)
Product (lb/day) = active polymer (lb/day) ÷ (active % ÷ 100)
Liquid product (gal/day) = product (lb/day) ÷ density (lb/gal)
Feed pump rate (mL/min) = gal/day × 3,785.41 ÷ 1,440

Notes & limitations

The dose basis matters: this tool assumes the jar-test dose is expressed as milligrams per liter of active polymer. If your lab reports dose as product, divide by the active fraction first — or enter 100% active.

Polymer overdose causes sticky floc, filter blinding, and carryover that can be worse than underdosing. Always confirm with jar testing; more is not better.
Make-down matters: most dry and emulsion polymers need proper dilution (often 0.1–0.5% solution) and aging time to uncoil before they work. A correct dose fed as a poorly made solution still fails.
Active content and density come from the supplier’s technical data sheet — emulsion products vary by brand.
This tool is for operational feed-rate setting. Confirm pump calibration with a drawdown test and follow plant SOPs.

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