my tips:
duncans are the #1 coral where polyp behavior doesn't indicate anything about the system, look at other corals to tell. Ive had mine close up for a month, then reopen, numerous times and all other corals were fine. It looked diseased, it wasn't, they're crazy that's all. What they do with polyps must align with some other planet's moon cuz it means nothing here
fastest growing LPS when directly fed. blenderize some Mysis and shoot it into the polyps a few times a week, sustain for 4 mos to get many more heads
don't dip them in stuff as a treatment for seeming ails...just put em in a known fine setup, await their normal behavior and feed em well
watch for that flesh below the polyp, which should be growing down towards the skeleton and not receding back up towards the polyp, feed more if this is happening. That tissue mass over the longer term is a better gauge than what the polyp does day to day.