I have a 30 gallon reef tank with a mushroom coral and a candy cane coral and a long tentacle green anemone. My salinity is 1.023 and my ammonia, nitrite and nitrate levels read perfectly at my water test (my nitrates read 0 on small test kit). My mushroom corals are doing lovely, I think. At any rate they are large and moving to new pieces of live rock and looking very beautiful to my untrained eye. However I have horrid, awful, green hair algae. I take the live rock out and scrub it, but my corals are moving on to other rocks, so I can't take every piece out. It turns brown and goes away for a few days after a cleaning, but always comes back. Any suggestions? A fish to eat it that won't eat my corals or a chemical addition?