Macro algea dying?

[Shirtlessbill]

Hey all, Only been on the saltwater side of this hobby for just under two years so this may be dumb but I just haven't seen it before. Tonight a large portion of my macro algae has turned white. Wondering what could be causing this. About 1 1/2 weeks ago I had a surplus in my refugium (in sump, and super green) so I took out about half to remove the nutrients from the tank. The only changes to the tank have been the temp has hit 80 a few times due to the cold weather here kicking in my house's heater and more frequent water changes due to a some cyano I noticed in my DT. My initial thoughts were lack of nutrients but that is debunked by cyano I think. Also, I'm assuming I remove the white bits? Seems like a nutrient factory if I leave it in. I was under the impression that these algae were very hardy but none of my corals seem unhappy so I'm at a loss. All parameters have been testing as normal

 

[woody390]

What macro algae is it? I'd pull it could be going a sexual

 

[Shirtlessbill]

What macro algae is it? I'd pull it could be going a sexual

calerpa and cheeto, also some red stuff that I can't remember the name to

 

[woody390]

Which one is going white?

 

[Shirtlessbill]

Which one is going white?

definitly cheeto. But it's just the main "ball" that I had in there floating around so it's all mixed. Could the shock of having more light be enough to do this? It was pretty dense before I cleaned our the refugium

 

[Shirtlessbill]

Well I got most of the dead parts out. Definitely
Still some green in there. Chalking this one up to a temp swing I had due to my ATO getting stuck and having to grab cold RO water to stabilize specific gravity (I added the fresh water to the sump) hoping that was all it was