take a 20oz. bottle or 2l and cut the top off enough to put it over what ever you are trying to feed and take a turkey baster and siphon some food and target feed your corals.(thanks to john and his wife at ATA)
A couple times a week should be great. You technically don't have to feed them but they will grow faster. The bottle trick works great when you have fish and hermits that like to grab the food before the coral can ingest it.
I target feed a few things here and there in my tank, when I do I have a turkey baster and a solo cup that's only used for Rod's food.. While the food is thawing in the cup, I take the time to blow off the rocks and all that jazz (wow.. Off track) I lighty blow water across the acans,hammer,favia,frogspawn and trumpets.. It triggers them to extend their feeding polyps.. Squirt the RBTA with Rods and the rest I distribute to all the LPS..