[MalHavoc]

A refugium adds *extra* nutrient export capabilities to your tank's filtration system. It also provides a safe haven for copepods and little critters to grow. You don't *need* one if your tank is already being filtered adequately. How do you know if you need one? Look at your tank. Measure your water quality. Do you have algae problems? Measurable levels of nitrate and phosphate? If so, a refugium will help. Do you keep fish that eat copepods like mandarins? You probably need a refugium. If you don't have algae problems, and your nitrate and phosphate measure ZERO, and you've already got excellent filtration (protein skimming, a deep sand bed, lots of live rock, other forms of filtration, etc), you proabably don't have to worry.