Algae ID

[ZzyzxRiver]

I went to bed with no unknown algae and woke up with bubble algae on one frag and whatever this is on another. What am I dealing with here?

 

[Formulator]

Looks like ulva, also known as sea lettuce. That stuff can become a problem quickly so I suggest getting it out. Some people with a lot of herbivores let it go, but that can be dangerous… If you notice more, urchins are a great CUC member to add.