Algae Identification

[R0L0]

Hey everyone. So recently I've had a bit of a algae outbreak on my new tank. I have never seen this algae before in my previous experience. I though at first it was just GHA, however it's a lot harder to get off and Is just in little clumps. Does anyone know what type of algae this is?

 

[R0L0]

A little bit of tank details. The tank JBJ 28 gallon nanocube and is about 3 to 4 weeks old and currently has live rock bought from a lfs, a pair of clowns' a a few coral frags.
Salinity is 1.026
Ammonia is 0
Nitrites is 0
Nitrates is .2

 

[R0L0]

Nitrates is .2

Nitrates is at 20*