Are you asking about the green algae attached to the wall or the cream colored algae on the inflow pipe? If it is the cream stuff, I don't what it is but I can tell you nothing eats it. I think its in the family of brown algae. In my case, adding a phosphate remover to the system finally got rid of it. I used the two little fishes phosban reactor to do it. Other than that, aggressively sucking it out of the system during water changes took care of the rest.
GFO, GAC, heavy skimming, and water changes with RO/DI will get that under control. Syphon off the algae growing in the tank along with that water change. Any animal that eats that algae will die after the algae is gone, so don't waste a critter's life. You just need to lower your PO4 and silicates.
