I see a lot of pool stores have "skimmer socks", or the same thing by another name. They are a filtering bag with an elastic edge that goes into your skimmer basket like a coffee filter goes into a Mr. Coffee, and hooks over the edge. It catches lots of fine stuff that normally would flow thru to the filter itself. You pull it out and rinse it when it gets dirty, replace it when it's worn out. You get 3 to 5 in a package for about $5.

That's it!