My breeding clowns are in a system with a macro algae polisher, fuge or whatever you want to call it. Its been runing about 3 years now with some partial water changes. I hooked a skimmer to it last month and failed to get anything much to skim for the entire month. So, I took the skimmer off. Not needed. It has a shallow sand bed and lots of caulerpa. I take very little caulerpa out of it for "nutrient export". Its got more breeding little things in there than I imagined it would. The glass is covered with limpets!