it has to be fine enough to keep all contaminants out.
foaf used to use a 24k gold metal filter/screen/mesh jammy,
now he just uses a single unbleached coffee filter.
trial and error have gotten him to this point. to each his own tho.
btw, the coffee filter doesnt even get fully saturated by the end.
maybe the white ones do? never used them.
in response to the time it takes to strain-
5 minutes and im done and doing dishes.
i understand what u are sayin, but it's a
quick wash --
if a filter is preventing draining into the evap dish fast enough,
its my opinion that you oughtta rethink your technique.
i dont have this problem, akoutdoors...but thanks for the suggestion.
anything will work as a filter. use what is convenient