Keeping color in rainbow trachs

[roshi719]

I have a rainbow colored trachyphyllia geoffroyi. Since I got it a few months ago it has bleached out on me. I believe this was due to a low Mag issue I had a few months back. I have since raised the mag to 1450, and everything else that had bleached on me has colored back up. The trach is still bleached though. I have been keeping it in the shade under a cap colony where it gets medium flow. The tissue still expands somewhat but not nearly as much as it did when it was healthy. Does anyone have any secrets to get these rainbow brains to hold their color, or have a way to color them back up once they bleach?

Here is a pic of it right after I got it for refference. I would show you a picture of it now, but I'm sure most of you know what a white LPS looks like.