Something you might try is adding a little DE powder to your sand filter. Many of us do this and it helps your sand filter to filter out things that are a little smaller than it normally could. It is a little tricky getting just the right amount. You can read more about it at the following link. Just something else to consider. Glad the pool is starting to look better!

http://www.poolforum.com/pf2/showthread.php?t=3742