Algae from H***

[Delphinus]

Looks like a little like dinos to me. Mine was a little different, it would sort of start off caked over things like that, but it would send off little streamers into the water column and then collect at the water surface in slower current areas in a sort of bubbly froth.

Does it disappear completely (or almost completely) at night and then come back the next day?

Maybe a sea hare would take to it? I had a refugium with the exact stuff (I assumed it was dinos but not 100% certain), and he cleaned it up within a few days. Of course, since it behaved like dinos it would come back.

I still have that sea hare, although I don't know if he'd still eat the stuff. He's stopped eating caulerpa and sargassum (he used to keep that stuff in check), but now that he's discovered TheYummyNori(tm) that's pretty much come to a halt. At least I don't have to worry about running out of food.

But if you see one for sale maybe it's something to try. As long as he doesn't get all aristocratic on you like mine did...