Richard, thanks for the input. It gets me every time (that the way I do things isn't exactly what's been posted), in this case, I make a 'bomb' out of the cya I add in a kneehigh to the skimmer. When I make one, I can put ~4 lbs into one and still 'double it over', with 2 layers of nylon, I can't believe that there are any 'chunks' to be trapped in the skimmer. FWIW, I TRY to refrain from backwashing for a few days after I've added the cya.
This discussion is sort of special to me as I have a customer who weekly tests low on cya (with a SWCG pool), despite the fact that I've added over 10 lbs this season (to a ~33,000 gal pool), (visible algae on the floor, no cl). ( I think her brother-in-law is removing my cya 'bombs' and tossing them into the woods).