I'd try a dip and low to mid light good flow. We got our 4 polyps at the grand rapids swap and have 5 with 3 babies opening. They have gotten to be huge polyps also way bigger the our magicians.
Big Steve
I wouldnt dip either- unless there were sighns of fungus, predators or irritators. Sounds to me like the polyp is stressed/unhappy- and a dip can further stress the polyp.
Is this polyp not opening the one we had to reglue? It might just need more time.