Not the cheapest but I don't have the luxury of as big of sumps as other people. For my 300 gallon running on a 55 gallon sump I have a marine pure bio block, 3.5lbs of matrix, filter floss, and some medium foam along with matala mat shoved in there for filler. First through a 7"x12" 100 micron sock, then through floss, then everything else.
I am thinking about dropping down to a 50 micron sock to try it out. Logically to me, the less particles that reaches the bio media that can clog it up the better.