birdnest growth pattern question

[carpus]

lately my birdnests (pink and green) have been receding. None of my other corals are showing any signs of "discomfort"


The birdnest skin recedes from the bottom and fade to a white. In some cases they expose skeleton, its a slow recession from base up.

I dont know if its a normal thing, like inner branches that are shadowed by the light dying out.

Both are placed really high in the tank, 10+ inches from the 2 250w MH. I know its not too intense because they show great PE and color. the only problem is the recession from the base.

Any suggestions?

ammonia/nitrate/nitrite should be around zero, but I'll check. I doubt they are the problem or all the corals would be showing signs.
ph 8
alk 8
temp 77-80

 

[twon8]

I think it is common, probably lower light and flow, the coral gives up that part. Is it receding faster than it is growing?

 

[carpus]

The colony it self is alot bigger than when I first got it. but the recession has started these past few months.

 

[twon8]

Try adding some more flow, see if that halts the recession.