How do alumina content and basicity affect Polyaluminium Chloride performance and pricing?

How do alumina content and basicity affect Polyaluminium Chloride performance and pricing?
Three quality indicators decide PAC's value: alumina content, basicity, and pH. Alumina content measures the active ingredient and correlates with solution density and viscosity; higher content means more effective coagulant per tonne. Basicity, expressed as the hydroxyl-to-aluminium molar ratio, governs flocculation behavior, with optimal performance in the 40-90% range depending on raw water turbidity. PAC's wide effective pH window of roughly 5.0 to 9.0 lets it outperform aluminium sulfate, which needs tight pH control and generates more sludge. These specs also segment the market: drinking-water grade at 29-30% alumina commands a premium over 26% industrial brown grade.