Many chemical consumption estimates start with the same question: “If my target dose is X ppm, how many kilograms do I need per day?” The answer is straightforward once flow and operating hours are known.
The basic formula
When flow is expressed in m³/hr and dose in ppm:
Pure chemical kg/day = Flow × Dose × Operating hours ÷ 1000
This follows from the approximation that 1 ppm in water is 1 mg/L.
Example 1: continuous operation
Flow = 50 m³/hr, dose = 8 ppm, operation = 24 hr/day.
50 × 8 × 24 ÷ 1000 = 9.6 kg/day of active chemical.
Example 2: partial-day operation
Flow = 120 m³/hr, dose = 3 ppm, operation = 16 hr/day.
120 × 3 × 16 ÷ 1000 = 5.76 kg/day of active chemical.
Correcting for product strength
If the 9.6 kg/day requirement must be supplied using a 12.5% product:
Commercial product kg/day = 9.6 ÷ 0.125 = 76.8 kg/day.
If the product density is 1.20 kg/L, the volume required is 76.8 ÷ 1.20 = 64 L/day.
When ppm is not enough
A ppm value is only the dosage target. It does not tell you whether that target is chemically correct. Chlorine demand, alkalinity, hardness, silica, organic load, corrosion risk, retention time and process objectives can all influence the real dose. Use ppm calculations to convert a validated treatment target into a consumption rate—not to invent the target itself.
Quick check
A useful sense-check is to calculate active kg/day first, then commercial kg/day, then L/day. If you jump directly from ppm to pump L/hr, concentration or density errors are easier to miss.
For repeated calculations, use the Ramven Chemical Dosing Calculator.