Rock Flower Nem looking dull

[graffitireef]

Hey everyone, hope 2021 is treating you well. I purchased a few rfa's from saltcritters.com about a month ago and so far theyve been spectacular. This past week I noticed one of them looking a little dull. It had neon green tentacles and its center was a lighter neon green. He now looks pinkish orange in the middle and has light neon green tentacles almost pastel. He doesnt seem to want to open up nor is he eating. Parems check out except for an elevation in phosphates due to some macro algae dying leading to a diatom bloom. He's been well fed and the other ones look ok. One moved spots and is in a cave and seems to be flourishing. Anybody have any insight to this? I know they dont like strong like and are all placed near the bottom of the LR. Im stumped because hes been fine with the lighting so far and never tried moving and Im using the A1 prime 16hd on relatively low settings.

 

[lapin]

I have about 15 in a 20gal tank. Some have changed coloration over time. I have some that moved to the bottom and some are just 1" under water directly under a A1 prime 16hd on settings just like
https://www.aquaillumination.com/signature_series/karen-vazquez