Hard Green Specks of Algea on Glass? Coraline?

I have a 10gal nano reef and I noticed about a week ago that this hard green algea is grwing on the glass everywhere. It's just little specks as the moment but to remove it I have to scrape with my fingersail. A normal magnet glass cleaner doesn't remove this kind of algea. Is this green coraline maybe? My parameters are:
Ammonia 0
Nitrite 0
Nitrate 5
pH 7.8
SG 1.024
Phosphate 0
Cal and alk I don't know because I don't have a test for it at the moment.

Could these little specks of hard green algea be coraline? Is there any other kind of hard algea that you wouldn't want in the tank? It seems to be JUST growing on the glass. On the sides, back and front, but nowhere else.

 

Yes, they most likely are.

 

ok, so it's nothing to worry about then? Just keep scraping it off the front of the glass I guess then lol, I'll leave it on the back though.