I am making corrections to a database of observations of phytoplankton samples. the point is that he needs to convert the observations into density (cel / ml). I found a formula that mentions. N = X * [(A * d) / (a ​​* V)]. where N) = cel / ml.

X) = Observed A) = Area of ​​the sedimentation chamber. d) = Area of ​​the optical field or grid. a) = dilution factor. V) = sedimentation volume. I was also given this data: Area of ​​the camera = 490 mm2. Optical field area = equal to the area of ​​the camera because it was observed complete (full sweep). dilution factor = 1 (sample not diluted). V = Sedimented volume (50ml for all samples).

in several samples, 1 to 30 cells were observed in some species. my question is: is it valid to say that when 1 cell was observed, its corresponding density value is 0.02 cel / ml? or is there any correction to the formula?. I thank you in advance for your answers.

PD: they only made 1 observation per sample, under a 25x magnification and total observation of the sedimentation chamber .