ATS/refugiums with macroalgae will be useful for any system, so Long as you have the space for it. If your sump isn’t that big, an ATS or macroalgae reactor would probably be more ideal. Big refugiums are most effective but to get noticeable results from them they need to be large, preferably 50% the size of your main display or more. For smaller systems with large remote refugiums, some can be so effective at nutrient export that you don’t even need a skimmer, just good lighting and macroalgae to soak in all the nitrates and phosphates. Sent from Singapore Reef Club mobile app