There are a lot of things out there in the market that are being sold for feeding corals. The real question is that, do they work. ? or just contribute to tank pollution.
There are a lot of us old timers who have kept corals successfully without directly feeding them, and have really good growth on the corals. Most of these tanks, do have a lot of fish and the fish are well fed.
My general rule is if it has a big mouth directly feed it. The rest I don't do much with direct feeding.
The products that I use are basically mysis shrimp, frozen cyclopeeze, and oyster eggs. This give a large enough variation in size that if the polyps want to feed they can.