Try getting some skimmer socks from Wal-Mart - or just cut the ends off some old nylons and put it on the skimmer basket.

Also - how long are you running your pump/filter a day? You need to make sure that you are circulating double the volume of water everyday.

Another thing you can do is purchase some DE and put some (I think a 1/2-1 pound) in your skimmer. This will go directly onto your sand filter and help filter out smaller particles. Be aware that when you backwash - all of the DE will wash out - so I would try this last.