What am i dealing with?

[PghReef]

So what is this? I'm thinking cyano and GHA with all kinds of stuck stuck in it. Phosphates are like 10ppb with checker, nitrates less than 5. I'vtried blackouts, large ac, nothing seems to work just come back. Tank is about 14 months old

 

[waleedreef]

it looks like cyano bacteria.

Cyano is bacteria which require light and phosphate and it like spots where no much water movement. manual removal everyday will help to limit the presence of cyano. Cyano caused due to imbalance of nutrient import and export going on. To solve this, you need to increase the power of gyres, manual remove, fix GFO to remove phosphate till 0.05. start adding carbon dosing such as NOPOX. If this not work, you need to start the antibiotic product called chemiclean or RED X.

you can also dose nitrate up to 10 ppm
keep phosphate up to 0.05

use GFO.