[Plankton]

Gone from trad cleaning (14yrs experience) to wfp, 6 months ago.
Did best I could in research on techniques n equipment.  Those first cleans from trad to wfp, were killers!
Now 6mnths in. Water in tank is 000, using a gardiner brush. I aggitate 2/3 times and rinse plenty. Yet on the top windows which open, above main window. They still spot and I dont kno why? Any help n advice? I rinse from the rubber seal down, to cut into top line, is this the course of my problem?

What I found with some hoppers is that they appeared to be greasy looking when scrubbed with a vertical or horizontal motion but if I used a circular action and then rinsed it appeared to be spotless. It's only a handful windows but after a couple of years I'm still extra cautious if there is beads of water on them.