What in the world is on my palys?!?

[SnazzyUrchin792]

So I have a colony of nuclear green Palythoas, and as I was observing my tank just now, I noticed these weird purple patches. Does anyone have any idea what they could be? They look like the actual paly is turning purple, and they do not blow off. I have had these palys for 9 months, and have never seen them do anything like this.
(And the purple tint over the 3rd and 4th photos is the effect of a filter. I posted them because the shade of the purple spots is more accurate to real life.)

 

[blaxsun]

Looks like you've got some algae growing amongst them.

 

[SnazzyUrchin792]

I know I have algae problems, I’m working on that. But could the algae be causing them to turn purple?

 

[SnazzyUrchin792]

Anyone have any ideas? Spots are still here today.

 

[bobnicaragua]

I know I have algae problems, I’m working on that. But could the algae be causing them to turn purple?

It’s kind of hard to tell from the pics, but the purple parts look unhealthy to me.

 

[Tcook]

I agree. The last pic at 11:00 on the disc some of the rays look flattened and necrotic. It’s hard to tell in the pics though.

 

[SnazzyUrchin792]

Might be hard to tell from the picture below, but the stalk and rays of some of them are turning the same shade. If it is unhealthy/experiencing STN, what could cause it? The only changes I’ve made recently are raising alk, lowering phosphate after a massive spike, and slightly changing flow. All other corals and a RFA are happy.
Edit: just remembered I’ve recently seen an increase in asterina/pod activity on their rock. Could this have anything to do with it?

 

[Rallic]

So I have a colony of nuclear green Palythoas, and as I was observing my tank just now, I noticed these weird purple patches. Does anyone have any idea what they could be? They look like the actual paly is turning purple, and they do not blow off. I have had these palys for 9 months, and have never seen them do anything like this.
(And the purple tint over the 3rd and 4th photos is the effect of a filter. I posted them because the shade of the purple spots is more accurate to real life.)

could the purple really be dark green and the lights are making it look purple? it looks like bubble to me