Dear Hilly, and Fixinspirit
Besides the white grains or fuzzballs (both of which are actually curled up strands of nematodes
http://nematode.unl.edu/wormgen.htm ....I've scoped them) have you seen any of the black pieces of what look like chopped pieces of black thread around your bathroom? That may be something entirely different, but I live on the water, so I am thinking I have that problem apart from what is in my body (the nematodes).
This pesticide thing is significant, I think.
Kritts