LOL! Dude
... It's not elongata, nothing close lol.
I all the tanks that I have seen it in - it is yellow. I wouldn't say it doesn't hold it color, Mine and Chris's has always been yellow. I have elongota, red sea, and bali giant and they don't look yellow I think it's safe to say it's not sulfer or iron rich waters that cause the yello coloring.
I feel this "Xenia" for the sake of calling it something is special. It is very diffrent from anything I have ever seen before. To the point that we tell people we have ENCRUSTING xenia and they think we're crazy, until they see it and then they are Whoa!
Again remember it NEVER branches AT ALL, it grows almost like GSP or encrusting gorgonians.. very cool indeed.
Cheers,
-Jc