Try filter socks. It worked for me. My overflows drop water so fast that is was causing bubbles and they were sent back up the returns and I had microbubbles in the main display.
Word of caution though, clean out the filter socks good and don't have them above your sump tank edge. Mine bubbled up and overflowed the edge which in turn went over the edge of the sump and got saltwater everywhere. Luckily I noticed it very quickly and it did minumum damage. Also if you don't clean them out good before use, it makes your skimmer go crazy. Don't know why but it did mine and the LFS skimmers.
The negative seems to be that you have to clean them frequently.