Need Help with this......

Ok, here I go. I am not new to this saltwater stuff, however I have been a fish only guy for a long time, I recently received a full 50 gallon tall saltwater fish tank setup from my brother-in-law who did not have the time for it anymore. We got it moved to my place about 1 1/2 years ago and now I am starting to see alot of things grow on the live rock that was in there. I have been able to name most of them myself but am not finding this one anywhere.

1. Can you please tell me what this is?

2. And also is it good or bad for the tank?

Sorry for the bad picture, but I can't seem to find my tripod. This stuff is darg and light green, almost looks like little "bubble arms" seems to stay on the two rocks that have it and does not really do anything.

Is it just a basic algae?

Thanks for your replys.

 

hmm do they look like mini green balloons? if so i think mexican turbo snails will take care of it...i know some ppl say emerald crabs do...but thats if ur lucky...turbos r better imo

 

Hard to tell from that pic, kinda looks like grape caulerpa.

 

or Valonia algae? It is difficult to tell.... :-/
Try to get a better pic ;D