You can remove it with tweezers or forceps (like tweezers but larger like 6" typically), and a bit of patience. Unless you have a really diabolical strain of caulerpa like I do, that still pops up years after I thought I first "removed" it. I don't know how it does it, but it finds spots to grow where I can't see it. How does it know I can't see it?
Weeeeeeird.
Anyhow, you can order forceps off the 'net or go to a home care shop (that's where I got mine, H&H Care or something like that).
Where ya located? If we're local, I actually wouldn't mind picking up a piece of that (trade you for some chaeto if you're interested)? It would make for an interesting macro in a refugium..