I know its high thats why I been doing weekly water changes instead of bi-weekly. its a 220g, 72''x24''x31'', 120 lbs LR in DT, 50 lbs LR in sump and 50 lbs LR/rubble in refuge. Sump is 40g with LR, filter sock and foam blocks that get cleaned every week, protein skimmer, phosban reactor and GFO...