Chemical Dosing Calculator for Water Treatment

Q: How do you calculate chemical dosing rate for water treatment?

The dosing rate in mL/min is calculated as: (Flow rate in L/min x Target dose in ppm) / (Chemical concentration in percent x Specific gravity x 10,000). For example, at 100 L/min flow, 3 ppm dose, using 30% concentration chemical with SG 1.1: (100 x 3) / (30 x 1.1 x 10,000) = 0.0909 mL/min.

Q: What is the typical antiscalant dose for RO systems?

The typical antiscalant dosing rate for RO systems is 2 to 5 ppm of the feed water flow. The exact dose depends on the feed water analysis, recovery rate, and the specific antiscalant product. Higher doses (4-5 ppm) are used for high-recovery systems or water with high scaling potential.

Q: How much sodium metabisulfite is needed to remove chlorine?

Sodium metabisulfite (SMBS) is dosed at approximately 3 ppm per 1 ppm of free chlorine to ensure complete dechlorination. A 10% safety factor is commonly applied, making the practical dose about 3.3 ppm SMBS per 1 ppm chlorine. This protects RO membranes from oxidation damage.

Chemical Dosing Calculator for Water Treatment | ForeverPure

Chemical Dosing Calculator for Water Treatment

Calculate precise dosing rates, daily consumption, and monthly costs for common water treatment chemicals.

Quick Presets (select a chemical or enter custom values below)

Flow Rate

Target Dose

ppm (mg/L)

Active ingredient dose in the water.

Chemical Concentration

100% for neat/undiluted products.

Specific Gravity

Density relative to water (1.0 = same as water).

Operating Hours per Day

hrs/day

Chemical Unit Cost

$/kg

Dosing Results

Dosing Formula

mL/min = (Flow [L/min] × Dose [ppm]) / (Concentration [%] × SG × 10,000)

Period	Volume	Weight	Estimated Cost

Order Water Treatment Chemicals from ForeverPure

We supply antiscalants, SMBS, caustic soda, citric acid, hypochlorite, and more. Bulk pricing available.

Shop Chemicals

Or call us: +1 (408) 969-2688

Frequently Asked Questions

How do you calculate chemical dosing rate for water treatment?

The dosing rate in mL/min equals (flow rate in L/min × target dose in ppm) divided by (chemical concentration in % × specific gravity × 10,000). This gives the volumetric flow of chemical solution to inject.

What is the typical antiscalant dose for RO systems?

Typical antiscalant dosing is 2–5 ppm of the feed water flow. The exact dose depends on feed water analysis, recovery rate, and the specific antiscalant product. Higher doses (4–5 ppm) are used for high-recovery systems or high scaling potential.

How much sodium metabisulfite is needed to remove chlorine?

SMBS is dosed at approximately 3 ppm per 1 ppm of free chlorine. A 10% safety factor is commonly applied, making the practical dose about 3.3 ppm per ppm Cl₂. This protects RO membranes from oxidation damage.