Hi McReef! That is definitely a very good argument in favor of refugiums and it was the original idea behind them. You have to remember however that foods vary widely between different species of corals. There are some such as gorgonians that will take live phytoplankton out of the water column but I know of no study that shows that any sps coral consumes phytoplankton. They do however, consume zooplankton. Even then, some species of corals take large zooplankton and some are only equipped to capture very small sizes. Much of what is produced from a good refugium is not mature animals but rather the products of reproduction and the larval and jeuvenile stages of the animals. These are wonderful sources of coral food for many species. And of course the delivery of the occasional mature copepod, amphipod, mysis shrimp, etc. is appreciated by many corals. Supplement with DT's live phyto and the smallest sized golden pearls and you have great food for deep sand beds, filter feeders and many species of corals in my opinion.
