Take a look at zanlus's website under soft... I'm thinking it's either green star polyps (GSP)or green hairy shrooms. If they arent open yet and all you see is a purple mat, then its GSP. Ive had GSP in varying flow from light to strong, but I think medium is best. Otherswise their always bent over in the flow and dont look as nice. Green hairy shrooms should be in low to medium flow.
Hope this helps.
Adam