ReefAddict.....My daughter and I have had great luck with our sun corals feeding them a whole cube of frozen "Prime Reef." Sometimes I give mine a cube of Krill cut up really fine. They also like occasional live brine. Mostly it's just the Prime Reef though. We take them out of the tank in a small tupperware bowl just barely deep enough to cover them in tank water. Then we swirl the water around with a turkey baster every 10 to 15 minutes. It used to take about and hour and a half for them to eat. Now it takes about 15 to 20 minutes. They don't eat too much at first until you get them trained and they get strong enough to open fully. We did this every night at first and now since they are trained, we feed them every other to every third evening. After they are done eating we just place them back in the tank
You can set the little tupperware bowl in the bathroom sink and add a little luke warm tap water to the basin if you are worried about temperatures cooling off too much. I used to do this, but now I just let the bowl sit out on the counter the whole time. They are really tough little corals and have not seemed to notice the temp change when I return them to the tank. They are hardier than most people think. I avoid poluting my tank by feeding them in the little bowls. They are really pigs and require a lot of food once you get them trained. Enough so that I know my tank would be poluted and they still wouldn't have their fill if I were not to place them in the bowls. That's why the "food bath" in the bowl works great! Hope you have good luck too