It can spread like wildfire, and is very difficult to get rid of. It can really overtake your take, smother everything in it's wake and you'll end up with a tank packed with the stuff.
I was ripping out around a kilo a week at one point, but you can never get it all, and any damaged parts that tear off usually attach somewhere and regrow.
Although having said all that, some tanks simply won't grow it.
I would try some in a very isolated location in the tank if you can, and see how you get on with it, but if it seems like it's growing exceptionally quickly, then I'd pull the plug on it before you lose control.