Elegance coral not doing well. Not sure what I did wrong

I have 2 elegance corals, both bought at the same time from my LFS about three and half weeks ago. One has purple tips and the other one has pink. I originally placed them in the sand bed as suggested by staff from LFS. They were opening well and have long tentacles. I start to notice the one with pink tip is not opening much and the tentacles shrunk significantly about 5 days ago. I thought maybe it's my placement or not enough flow in my tank. Try to move to a few places, no improvement. I also add a new wave maker a few days ago. Hope things will improved. From what I read, is it because my light setting is too strong for it? Or I move it too many times causing stress? Or is there other problem in my tank that I didn't know about?

I am new to this hobby and this is my first post. I am really worried that my little elegance coral won't survive if I don't identify the problem. I also have 2 hammers and 1 Duncan. I think they are fine.

My water parameter is pretty much the same. Salinity is 1.027. No3 <0.25ppm Po4 0ppm Ca 425ppm. KH 7.7 dkh Mg1460ppm.

Any suggestion or advice will be greatly appreciated.

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