I probably could, but I like the fact the protein skimmer directly lifts long chain organics directly out of the water. The sand filter is basically a backup to the algae scrubber, as it cycles itself (found that out the hard way, the algae actually changes it variety and characteristics). As long as you aren't adding chemicals, I don't think you can over filtrate the water. My system is almost always run "open" with no fine filter blocking small organism growth. The only time I filter particulate matter is if I am stirring things up and cloud the water.