i think i just found it and it's called maiden hair algea...it grows thick in strands just like grass...this is what i found
"Maiden's Hair algae provides a very soft appearance combined with all of the other benefits of macroalgae. Maiden's Hair looks like a thick mat of bright green carpet, adding an intense green color and soft flowing motion to any marine aquarium. Most Maiden's Hair is collected off of the islands of Tonga or Fiji, and comes already attached to a small piece of live rock."
