Choose the experimental decision
Name the raw-water question, candidate panel and acceptance measurement before preparing stocks.
Separate coagulant screening from full-scale treatment approval.
Preserve the water and controls
Use a representative homogeneous sample at the intended temperature with untreated and incumbent controls.
Record starting pH, alkalinity and any sample aging or settling.
Declare the dose calculation
Write supplied-product dose and the normalized aluminum basis with stock preparation and age.
Do not compare liquid volumes and powder masses without the required conversions.
Reproduce the sequence
Keep addition order, rapid mixing, gentle flocculation and separation timing matched.
Ensure the procedure is feasible in the installed plant rather than extending time until one candidate looks good.
Interpret more than the best jar
Record final pH, treated-water measurements, floc behaviour and relevant solids or filtration consequences.
Repeat decisive points and retain the complete result table, not only a photograph of the best beaker.
Carry the treatment evidence into purchasing
Keep water analysis, product identity, preparation, final pH, mixing and separation results attached to the buying decision. Resolve the relevant next questions with PAC vs PAM Flocculant: Which Chemical Should You Order?; PAC Trial Order: Set Plant Acceptance Before Bulk Purchase.
A technically accepted candidate still needs an identifiable supply scope, current product documents and a feasible delivery and receiving plan. Record any conditions still pending. Changes in formulation, water source, production state or treatment equipment should trigger review rather than automatically inherit an earlier approval.
Interpret the PAC jar-test result
Prepare one homogeneous batch of representative raw water and keep it at the plant-relevant temperature. Measure the starting turbidity, pH and alkalinity before dividing the sample. Include an untreated blank, the incumbent coagulant and coded PAC candidates. Express every addition on a stated product or active Al2O3 basis so the dose ladder can be reproduced and commercial comparisons are not distorted by different product concentrations.
Use the same stock-solution age, addition sequence, rapid-mix energy, flocculation stages and settling time for every beaker. The dose series should be wide enough to reveal underdosing, a useful response window and any deterioration at the high end. Record floc onset, size, breakage and settling, but rank candidates by the treated-water measurements that matter to the plant rather than appearance alone.
Measure settled turbidity and final pH at minimum; add color, UV254, phosphorus, residual aluminum, sludge volume or filter response when those results govern the duty. A single best beaker is not an operating range. Repeat the most promising points around the apparent optimum and then challenge them with a credible difficult-water condition such as lower temperature, lower alkalinity or higher contaminant loading.
Transfer the result into a field-trial sheet that states product code, lot, water analysis, stock preparation, dose basis, mixer settings, timing, sampling points and acceptance limits. Confirm pump calibration before scale-up. Jar testing ranks candidates under controlled conditions; full-scale release still depends on the installed hydraulics, solids loading, sludge handling and downstream filtration response.
When results are close, repeat the center points in duplicate and randomize candidate labels before review. Preserve photographs only as supporting evidence and retain the raw measurement sheet. Report analytical detection limits and any sample settling that occurred before testing. These details make a later supplier comparison or seasonal retest genuinely comparable instead of relying on memory or one selected image.