Nuisance plant?

[BNS77]

I'm not new to the hobby, I need some help IDing this plant. I bought some live rock from a guy who was breaking down his tank. All but one rock has been great, but after about a week this plant began growing from this rock. This stuff grows like Kudzu and is growing over a lot of coral. First of all what is it and second how do I get rid of it. I've done several water changes think that would solve it but to no avail. Thanks!

 

[phobos2deimos]

That's Caulerpa Serrulata, and isn't particularly a nuisance compared to so many others (in fact, I love the stuff), but can be very difficult to remove from rocks once it gets hold. Manual removal where possible (get *every* little bit), and tangs or blennies may prevent any leftovers from gaining a foothold. Water changes probably won't do anything, but blacking out all light from that area *or* blasting it with a TON of light may help kill it.
Mine dies out under high lighting with LEDs, but that may encourage other nuisance algaes to take its place.
You could move it down to your fuge if you have one, I don't think it's very likely that it would make its way back up to your display again.

 

[BNS77]

I'll try a tang. I love them but haven't had one in a while. Thanks for the info.