How often do you feed your SPS?

[Willito]

What caught my attention about feeding is from the many ocean/reef DVD's that I've seen, they all show feeding routines that occurs from the depth of the sea. Massive amount of zooplankton would rise from the deep and it virtually feeds anything and everything that has mouth(s). Rarely do they show sps feeding, more often it's soft corals and anemone, leaving me to wonder, what the heck do they eat?