Wow! Sounds like that pool store guy is a keeper! There are some...I know one in Greenbrook, NJ.

Are you soaking it in electric dishwasher detergent? That's supposed to be the best. Also there's a hose attachment specifically for cleaning carts that may help.

Finally, when you put it back in, immediately get "Skimmer Socks" (also called "Filter Savers") They are pretty cheap, go in the skimmer as a liner, and will catch most, if not all of the pollen. Some years it's so bad I feel like I'm scraping yellow spackle off the Skimmer Sock. I find they last 2 weeks to a month, and usually are 3-5 of them for $10 or less, depending on the brand. They are actually one of those super cheap gadgets that really does work.

Carl