How much should I dilute my sample if the starting concentration is unknown?

If you don't know the starting concentration of the raw sample, we recommend doing a serial dilution of 1:10, 1:100, and 1:1000. Start the analysis with the most dilute sample (1:1000). 

A coincidence event is when more than one particle passes through the sensing zone at once. If the particle rate is higher than recommended, the software will overestimate the calculation for mean size and underestimate the calculation for particle concentration. If the particle rate is above/below the recommended value, increase/decrease the sample dilution.