Just want to verify, you mean this stuff:
I had this also, had no big problem with it, but when I wanted to put some SPS where this stuff was, I just plucked it out. Can't you just grab it and remove it? Just wondering...
Researching things I found this: Similar to chaeto, few animals will eat Halimeda except for one echinoderm, an urchin called Clypeaster rosaceus