So I have a nano 21 gal cube nano reefer tank. Excessive Ditritus is settling aroud edges of the reef rock. I'm only conserned because it looks ugly and I'm not sure how to deal with it. I'm maintaining 0 nitrates and near zero phosphates. My return pump is over sized its a jebao dct 6000. It produces about 1500 gal per hour i use it at about half power though 750ghp. Any advice I don't want anything that will bother or steal the corals food. I do water changes once a month. I'm not sure if there is any other details i can give but thats my problem.