I usually offer my LPS corals food whenever I feed the tank if they are hungry they will open up if not it will float into the tank for the other inhabitants to eat.
Mike
Personally, I don't spot feed any of my LPS anymore, they technically just get fed when I feed the tank. I'll sprinkle cyclop-eeze into the tank once ever couple days and once a week I feed with a bunch of mysis shrimp.