Everything I've read suggests that SPS are carnivorous. Cyclop-eeze may be too large though. I feed a mixture of Kent's Zooplex, Phytoplex and DT oyster eggs. I've seen a bit of a feeding reaction, but not too much, so I don't know if it's helping or not.
I run a very "natural" tank setup with mostly live rock and sand for filtration. I may have enough plankton in the tank in general to support their feeding requirements. FWIW, I have baby Banggai cardinals and a few 1-1.5" maxima clams I don't feed that grow and do very well, so I'm guessing there's enough microfauna in the tank itself to handle the SPS.