Every PAC inquiry we receive eventually arrives at the same question: "how many tons per month do I need?" The answer comes from one number you must measure (the mg/L dose your water actually requires) and one number you already know (your daily water volume). This guide walks through the calculation the way our technical team does it with customers in Vietnam and Indonesia.
There is no universal PAC dose. The right number depends on your turbidity, organic load, pH and temperature, and it is always determined experimentally: run jar tests on your actual water at a series of doses (a practical ladder is 10, 20, 30, 50, 80, 100 mg/L), pick the lowest dose that meets your clarity target, then verify it holds across a day of raw-water variation. As rough orientation only — surface drinking water often lands in the 10-50 mg/L range, while high-turbidity industrial effluent can require 100-300 mg/L or more. Never purchase against the orientation numbers; purchase against your jar test.
The conversion is direct: 1 mg/L in 1,000 m3/day = 1 kg/day. So:
Daily PAC (kg) = dose (mg/L) × flow (m3/day) ÷ 1000
Worked example — a plant treating 10,000 m3/day with a jar-test dose of 30 mg/L: 30 × 10,000 ÷ 1000 = 300 kg per day. Over a 30-day month that is 9 tons of PAC powder.
At our reference FOB price of US $230–350 per ton (powder PAC, Al2O3 28-31%), that 9-ton month represents roughly US $2,100–3,150 of chemical cost FOB — before freight and local charges. Running the same calculation at 60 mg/L doubles the budget, which is exactly why the jar-test step is worth doing carefully: the difference between a good dose and a lazy dose is often 30-50% of your annual chemical spend. Liquid PAC (Al2O3 10-12%, US $150–190 /ton FOB, MOQ 20 tons) prices lower per ton but delivers less active content per ton — compare products on active Al2O3 delivered to your tank, not on ton price.
Once your plant runs on the jar-test dose, track the actual consumption for two to four weeks and compare with the calculation. If reality drifts far from the estimate, the usual suspects are a changing raw-water source, a dosing pump calibration error, or over-dosing by operators "to be safe" — that last one is a pure budget leak. When the number stabilizes, we recommend contracting a standing monthly quantity with a fixed price band; you get supply security and we can hold the grade consistent batch after batch, COA included.
Related product: PAC Powder (Al2O3 28-31%) · PAC Liquid (10-12% Al2O3) · More guides: PAC vs PAM selection · Sodium acetate carbon source cost