What kind of Algae is this?

[Bryce Mazloum]

it's been appearing on my rocks and sandbed for the past week, in terms of testing I don't have a phosphate test kit and for nitrates I believe they are between 0-5ppm when I used the API test kit, any help would be great

 

[jeffchapok]

If it blows off easily, it could be diatoms. Is this a relatively new tank? If so, that's one of the ugly phases it goes through and they'll go away on their own in a couple of weeks.