need help badly brown hair algae

had a sever hair algae outbreak. I try to do research but everything on google comes back over 5years ago. with todays info things have to be simpler.

all started when i bought a watchman goby for a pistol shrimp i had. all of the sudden the shrimp was stirring all the sand with gave me a diatom outbreak. I also purchased a new led light and boom. diatoms and algae all over the place.

anyway, all the green algae is now brown. i think it died off only its not clearing up. will it clear on its own over time and i should just leave it alone? i put a small cuc in there but seems to be taking forever. I am thinking of doing a 3 day blackout but have some small frags in there and not sure how 3 days of darkness will affect them. Also dont like letting my fish starve 3 days.
also have small cyano but not too bad.

i guess my question is if i do a 3 day blackout, will all the brown algae clear up or will it still be there.

I have a 93 gallon cubed tank small bio load.
1 yellow tang
2 clown
1 blood shrimp
1 sea cucumber
1 cleaner shrimp and the darn pistol shrimp

nitrates 0
phosphate now reading .05 best reading yet even tho im sure there is more
alk 9.0
magnesum 1280
cal 440
ammonia 0
ph 8.2

i do have a lot of flow in the tank and read the flow is not good for algae. not sure tho.
thanks so much for your help in advance guys. ready to scrap this tank lol..

ps tank is about 2 years old with 4 inches of sand
started adding corals 6 months ago. i think that covers everything