elephant ear dying?

[Electriclou]

hello all! New member here!

I bought a huge elephant ear last week and it was great until 2 days ago when it started to shrink and look bad. I know they change shape with night and day but it doesn't look like that.

All my specs are stable. Only my Nitrate is higher that it should be (20ppm)
could it be only a nitrate problem? Other corals are looking great (elegance and finger leather).

Thanks in advance for you help
Lou