dt live phytoplankton regular or new premium reef blend, o rphytofeast live phytoplankton. all the dead stuff will just foul your tank but live phytoplankton is #1 in the ocean food chain. everything benefits, from the small fish to the corals to the small shrimps and copepods and amphipods that feed the smallest coral polyp. always follow directions and don't use more than recommended on the bottle or by fellow aquarists. the coral tissues love the omega fatty acids but you got to remember keep phosphates, nitratates, nitrites, and ammonia as low as possible via phosphate reactors, carbon, or refugium with various forms of light, filtration, and culerpa.
I use liquid life bio plankton and phyto plankton. IMO Don't over feed phyto because it can bring on some nuisance algae's. At least this has been my experience with DT's.
I have read its good for the sand bed so I add it once in a while.