What is a Refugium?

A refugium is just as it says. It is a refuge for macro algae (nutrient exchange) and for pods to growth without predation. Their are many types (separate tank, hang-on-back HOB, or a separate compartment in the sump. They are great addition to any reef to get a jump on pod (amphipods and copepod) growth for your system. Macro algae (caulerpa, gracilaria, chaeto) The one that most use is chaeto l- looks like green brillo or spaghetti. It doesn't go sexual and mess up your water. I have caulerpa prolifera and chaeto....just have the light on 24/7 to keep it in check.