Just a thought, there are different types of refugia that can cultivate different types of micro-crustaceans and plankton.
Like mangrove refugias, turf scrubbers, refugias for cheato, caulerpa and seagrass, as well as lagoon style for LPS.
Refugiums can be set up as reactors for zoo or phytoplankton and plumbed in post skimmer.
Delbeek's Volume 3 has some really good information on different systems and talks about Miracle Mud.
But back to your point you are still skimming out food.