Brown Algae

[Gvirgoan]

50 gallon Tank has been up and running for 3 years and this brown algae just came out of nowhere. I lost my shrimp, starfish, and Blenny since this has happened. My Xenia has shrink and other corals are closed. I have 7 fish remaining that seems to be doing ok. Do I have Dinos ? Or is it diatoms that none of my clean up crew seems to be eating ? Algae did have bubbles but they seemed to disappear since I’ve turned the lights out for the day.

Ammonia 0
Nitrite 0
Nitrate 20
Phosphate 2
2 clowns
1 Royal Gramma
1 YWG
1Green Clown Goby
1 Mandarin
1 Cardinal

 

[aggrofish]

when you say Phosphate is 2 do you mean .2 or 2?

 

[Gvirgoan]

2.0

 

[moz71]

That phosphate is HIGH! Need to lower. With GFO (phosphate remover). Can’t really tell in pics but pretty sure you have Dino’s the way you are explaining it!