[flamingo]

Did you mean macroalgae?
You could add it, but try for a species that doesn't go sexual, if you really don't want to worry over it possibly crashing your tank. I personally like halimeda, which can still die down a bit at times, but nothing like the common caulerpa...

I agree with Pred, also shamelessy plugging in another forum here, but nano-reef.com's classified section, gets a few smaller spearer types for sale around there. You can also look around any big reef site/saltwater forum, and you'll usually find someone with a hitch-hiker that came on their live rock.