The only issue that I have found with Halimeda is that my urchin would plow through the stuff like candy.
The urchin had pretty much eaten all my halimeda before I loaned out my urchin to my father in law.
It also doesn't do well with competition from other algaes. My capula (spelling bad, sorry) would start to grow on it, turning the halimeda white over time.
Nice part about Halimeda is I let the "dead" pieces of halimeda stay in the tank, and my hermits break it down back into the DSB.