Bringing Back Zoa Colours?

[Oscar]

Probably 6 months ago I finally solved my hair algae problem. But one issue that has never resolved itself is that a portion of only zoa colony lost it's colour and has never come back.

This was the section that was covered by the most algae. Funny thing is, the portion of the colony that was not covered in algae is expanding with it's original colour.

Reef Central has had some discussion about dosing Vitamin C to sharpen the colours. Not sure that I want to try that.

Anyone else ever resolved this issue? If I cannot bring the colour back then that portion of the colony will be removed. I just do not have enough real estate.