Botroycladia is what my original Google research said, but there's only one or two pictures that actually match mine, and neither give much info. One of the guys on RC that has a marine lagoon (a beauty!) has something like mine, but never mentions if it's one of the ones he encourages or a pest.
No those crabs are fine. They suposedly eat bubble algae. People say to get them as juvenile's or as small as possible for the best chance they will eat it.
From what i read on Botroycladia is that the one that grows on stem's is kept, but if its spreading on the rock its considered a pest.Either way i'd get rid of it.
Emerald crabs are awesome lil dudes. I've never had a nuisance one and they will munch that hair algae as well. Some people have had them nip at soft corals but I've never had a problem.
So I think it's fair to go ahead and identify this stuff. Here's a photo from today. Light adjusted, it's a darker red in person.
And here's the photo I'm saying is identical.
Picture is from this website: http://www.wetwebmedia.com/RedAlgID8.htm ID is a nemastoma sp. which is the same species I posted a picture of further up in the thread.
Also have some kind of other red macro growing nearby. Maybe a dragon's something-or-other?
Side note - I did buy an emerald crab to tackle the green bubble (and red bubble, which I have elsewhere in the tank). He is plowing through the turf algae, but hasn't left under the barnacle yet since the big bully clowns attack him when they see him (the barnacle is where they lay). But he's got plenty to eat on there anyway. Neat little creature. Thanks for the recommendation!
Just wanted to post an updated photo because I hate coming across old threads where no consensus is reached when I'm trying to research. If you have what's in my photos - DONT PULL IT. Here it is grown out:
It's a nemastoma that LA Reefs calls the "red air dancer". I've sold $75 worth of it on eBay in 3 auctions. Sweet little find!