I had some in my old tank and also in my new tank. I noticed that they are not happy at all if your nitrates are too high (as with most things) and lighting I think is not that important. My current tank has some strong water movement and the star polyps love it. In fact they have spread really quickly and the polyp extension is really good.
They did not thrive in my old tank and I did battle with high nitrates, but my current system is many miles apart from the old one.
So, all I would say is that if they are in a good flow and the water quality is good then there shouldn't be a problem. Give them a bit more time time and see how it goes, mine did take nearly a week to open up when I first got them and now they are open all of the time (they are the first to open in the morning and the last to close at night).
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80gal with live rock (35kg/70lbs), 30gal sump, refugium with live rock, chaeto and DSB, Bullet-1 skimmer, Fluidized Reactor, T5 lighting (6 tubes), 4 x Koralia 3's. | 
