Hi all, just wondering if i should clean up my sump/refugium. I only have a skimmer, chaeto, and a bit of rubble in the center section. No mud or sand. Have tons of tiny shrimp, amphipods and pods. Don't have a nutrient problem at the moment. NO3 is 4ppm and PO4 is at .12. Cheato is grows well but am starting to see some cyano pop up on the cheato. Not sure how to clean it without sucking out some of the critters living in there. Any thoughts?