well im not just using the filter sock for the filtration i have a skimmer and live rock/sand in my refugium along with macro algae. I do think I could use more rock rubble though. Also i have my skimmer on a stand that I made to raise it off the bottem to the right level. I noticed that I still get the brown waste in the first chamber under the skimmer stand. Would adding rock rubble under the skimmer stand hurt the way the skimmer functions?