Algea ID - Please

[Denali]

Any shared knowledge would be greatly appreciated. Tank have been progressively declining for about a month. Most coral has died, some still holding on...

I work 100+ hrs a week so, i Haven't tested much off anything. Just started my days off so I need to get this squared away.

 

[Udest]

Oof first thing you're gonna want to do is get as much of that junk out as possible. From what I can see looks like some cyano and hair algae everywhere. Also a substrate rinse can help too.
Over all you need to get a lot of nutrients out.