I feed lots of nori, emerald entree, selcon, rotifer powder and copepod powder, the red bacteria powder , pellet.Even a plain ole finger sponge will last them a very long time, as long as you are feeding them other food. I have a red finger sponge that is 3 years in my tank, 2 yellow sponges about 2 years that my eblii munches on from time to time and they are not affected at all. Granted he is a sump fish now, just due to me tearing down the macro tank, but he hasnt touched a single coral in all that time. He also has macro, sponge and other foods to eat.
I feel that if you can provide close to the diet they need (not what you think they need) then they leave corals alone. Same goes for Foxface. I have only had 1 foxface that ate corals. Towards the end of me being in the military, I was not home and it was only getting frozen food. It then decided to eat corals. Once home, I started giving it plenty of macros to eat and eating corals stopped. It was like it was missing some nutrient/vitamin or something from the macros and decided it needed to eat corals to get it.
I do want a macro tank eventually that I can harvest some algae to feed