The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Unless you have fish that eat it as fast as it grows I would put it down in the sump, Caulerpa racemorsa (green grape) grows like a weed at a high rate and reproduces quickly .
if you like this type of plant there is a similar plant that's not evasive it is called botryocladia most know it as red grape caulerpa even though it's not a species of caulerpa . http://marineplantbook.com/marinebookbotryo.htm.redgrape