I don't know what size particle the scum sock filters so I can't tell which catches the smallest particles of the two but it is easier to dump and rinse the skimmer basket and scum sock than to backwash your filter especially this time of year when pollen and other tree droppings are heavy. Also, while you have to take the skimmer basket out to clean it, your filter is ALWAYS there doing its job so there will be some junk that sneaks by when you put the skimmer basket back in that your pump basket may or may not be able to catch.

The scum socks are more valuable for a cartridge filter since there is no backwash option - you have to open the filter up and manually clean the cartridge when it is dirty so it is much easier to rinse the sock than clean the filter.

Over the weekend, I dumped the skimmer basket as least twich a day between the pollen and oak tree droppings. The skimmer basket would have caught the droppings but not the pollen.

Peter