Briefly, a PB-900 programmable six paddle jar stirrer and B-Ker2 gator jars (Phipps and Bird, USA) containing 2 L of cyanobacterial-spiked waters was used. Coagulant (either aluminium sulphate as Al2(SO4)3•18H2O (0–100 mg L−1 ) or ferric chloride as anhydrous FeCl3 (0–60 mg L−1 )) was added while stirring at 200 rpm (G= 480 s−1 ). After 1 min the speed was reduced to 20 rpm (G= 18 s−1 ) for 14 min. The samples were allowed to settle for 15 min. Samples were taken from the resultant supernatant to determine cell counts, cell viability and metabolite concentrations.