ID this on my birdsnest please

[cnreef]

Just wondering if this is something I need to be concerned about on my birdsnest. It seems to be growing fine but at the base there is a dark green coloration on two of my frags. I think its very slowly spreading upward but its hard to tell. Anyone have any experience with this issue? Thanks.

and with flash to show it better...

 

[PL-Reef]

Looks like algae taking over dead tissue.

 

[cnreef]

Hmm okay, I've just never seen it so dark and encrusting on anything else but my birdsnest. Anyone else ever have this issue?

 

[Grandlotus]

Check your phosphates.
Do you run GFO?

Looks like algae to me, is it soft to the touch?

 

[cnreef]

Well I believe I do have a phosphate issue. My phosphate test shows 0 ppm yet I have algae film on my glass that grows faster than normal (within 2-3 days after cleaning). I do not run gfo at the moment but within a month I will be adding a sump to the tank and running gfo for it. This will hopefully resolve the issue. I also have some chemipure blue that I could run in my ac70 until my sump is up and running.

I just touched it for the first time and it is not soft, feels hard just as if I'm touching the skeleton of the coral

 

[Reef Bass]

+1 for algae growing on skeleton.