Bill - my info on chlorophyll is from doing the Standard Methods test for chlorophyll. They filter the algae, grind the filter with the algae in a tissue grinder using 90% acetone with 10% water saturated with MgCO3 as the extraction fluid. Then we centrifuge to get rid of the tissue and filter residue, and then analyse it for the chlorophyll content. So that's where my thoughts come from.