Phytoplankton, analysis in FCM is done usually setting Red as threshold. PMT voltage is usually set by running blank sea water and increased until noise appears and event rate below 100/s. Then a sample is run. However my event rate only marginally increases say from 40 in blank to 70 in sample. Further running beads (1um) will again addup to event rate..but again only marginally say about 100 event/s. As far I know according to probability statistics for enumeration of random population, event rate should be much higher ..but below 1000 events/s. Correct me if I'm wrong.in that case Should in.increase PMT..of red ..then noise will increase..along with population..then.shall I simultaneously increase threshold so that.noise will segregate from.poupulation.and event rate improve..