IMO the strongest feed for them is mysis shrimp and cyclopeeze mixed, but blenderized not as whole mysis. That product you have above is ok too but they w go crazy for blenderized mush trust me it will make them reproduce sustained long enough
I have a sun coral that I target feed Tropic Marin pro-coral zooton about once a week. I feed it in the evenings when the lights are dimming because I have noticed that is when it opens up. In addition, what ever food floats off, my other filter feeders will grab. This is the first sun coral I have had (about 2 months) and its pretty easy to keep. I read that it does not like alot of light so I have it under a little alcove. As a matter of fact, I read that when they are taken out of the reef, they are found attached to the underside of the rocks. Hope this helps! See attached pictures!
Blue Lip is right, I assume my sun coral does get some left over flake food and other foods I feed my fish. I have seen it grab the food floating by which includes mysis and cyclopeze. But when I want to feed it individually, I used the Tropic Marin or any other food I can target feed.
I feed mine anything meaty and mushed up, usually a mixture of brine, mysis, prawn, lobster eggs etc. They get fed
this every other day.
As for lighting mine is directly under my light about 12" deep, people think that because they are Nps they should be in the shade which is just not true. In the wild they are found everywhere from the top of the reef in full sun to pitch black caves with no light at all.