Not sure what this algae is, it doesn't look like GHA but I could be wrong. It's growing in circular shapes that if removed stays intact. It almost seems like a type of seaweed.
Thanks, I've been watching it as it grew out and it never had that bubble shape I see in pictures online so I kind of figured it couldn't be bubble algae. Going to look into the sea lettuce and see what rabbit hole that leads me down.