What kind of algae is this?

[ScottyD36]

This kind of Algea has popped up on my top layer of rock closest to the light is this problem algae or is it OK.

 

[Beau_B]

Appears to be ulva, but a little hard to tell. Green potato chips?

It is a macro algae. A few things eat it, tangs and urchins for example. It may die back on it’s own if you get your nitrate under control.

edit to add: I keep it in my fuge for nutrient control. Aka sea lettuce.

 

[ScubaFish802]

Appears to be ulva, but a little hard to tell. Green potato chips?

It is a macro algae. A few things eat it, tangs and urchins for example. It may die back on it’s own if you get your nitrate under control.

edit to add: I keep it in my fuge for nutrient control. Aka sea lettuce.

That's what it looks like to me as well. But also hard to tell the shape with the one photo

 

[Big C]

Agree, looks like ulva. I had a outbreak in my display, pain to get rid of it. Tangs keep it trimmed back but nothing really eats it down to the scape except urchins so far. (sea hare didn't cowrie snails didn't). Peroxide outside the tank works but a lot of my rocks are cemented together (another issue.....) and difficult to remove/scrub.

 

[ThePurple12]

It looks nice IMO, but yeah it’s ulva. Lots of fish will eat it.