Biofilm in potable water - (Mar/16/2010 )

Yeah, like phage said: you need to know the mass of an empty cell.
And then every time you do your experiment you see what the mass is, substract the mass of an empty cell and you know how much biofilm you have.

First dilution? There is nothing difficult about that? Just pick a certain amount to dilute in. How much water you need the first time is hard to tell, you will need to find that out by trying.