Need help with Algae ID

[Navarchus]

Looks to me like part of the cycle....typical for new tanks.....will go away in time and you can use some cleanup crew. You should keep your system clean from:
No3 caused by over crowding and insufficient way s to remove it.
From po4 caused by over feeding and insufficient filtration.
Also make sure you don’t over light and not under flow….

[Twinn]

Yes I use RO/DI water and this is post cycle. Flow isn't an issue because where the algae is the worst, is where I have the most flow. Algae looks like grey or brown hair stuck on the rocks.

[christyf5]

Have you added any livestock to the tank lately, sometimes the cycle doesn't catch up and the tank can go into a mini cycle??