[Bezoar]

Most corals don't feed on phytoplankton directly. Feather dusters, gorgonians, clams, and coco worms are a few of the filter feeders that do. Unless you have an organism that does, adding phytoplankton will only foul the water. I culture rotifers for the coral but don't target feed any of them, just add it to the tank about every 3 days or so. You might want to look at Eric Borneman's Aquarium Corals, it addresses most of the nutritional needs of the corals we frequently keep.