Table 1. Preparation and processing times for algal-counting methods.

			Operator time for counting (min) b
Line	Method	Instrument preparation time (min) a	1 sample	16 samples	96 samples
1	Hemocytometer	1	6 c	96	576 d
2	Dinofinder	1	10	160	960 d
3	Coulter Counter	16 e	1.5	24	144
4	Guava flow cytometer	12	0.25	0.5 f	3 f

^aThe time required for the user to prepare for counting, independent of the number of samples to be counted. Based on multiple trials in our laboratory.

^bThe time actually expended by the user, independent of machine-running time for the Guava. Based on multiple trials in our laboratory.

^cCounting 16 1x1 mm squares. The four corner squares were counted in each chamber. Thus, two loadings of each sample were performed, which increases the time required for counting but decreases the chance of being misled by a poor loading of the chamber (one of the well known sources of systematic error with the hemocytometer).

^dOn the rather unlikely assumption of an indefatigable user.

^ePreparation time can be considerably longer if the instrument clogs.

^fUsing a multichannel pipet to load the wells of a 96-well plate.