I used a filter sock for years. 100 micron. Pulled it out for a week and plumbed a reverse durso ... experimenting while waiting on a larger sump. There was far more detritus and sediment on the floor of the sump in the week that the sock was removed than there was after a year with the sock in place.
So I put the sock back on when I plumbed in the new sump.
Filter pads catch some of the detritus, but not as much as the filter socks do. But either way, pad or sock, make sure you replace them with fresh pad or a clean sock, frequently. I replace my filter socks atleast 2 x per week. You wont have any nitrate issues contributed by the pad/sock if replaced frequently.
The skimmer will not pull it all out because much of it ends up settling on the floor of the sump.