in the ocean, sun corals grow in shaded areas, not in direct light. this is why i mentioned to place it in a shadowed area. yes, you can train them to open in the day, but i don't think you are going to be able to do so in direct light, half way up the rock.
if it's not an ORA mandarin (the selling point of those is that they are already eating prepared foods)then it's not the same. i suggest against purchasing a mandarin that doesn't eat prepared foods for a 34 gallon tank. it's very likely to starve.