I have a 10 gal nano that I've had for about 4 months now. I have 80 watts of PC and the tank houses 1 damsel, an
emerald crab, 2 snails, some xenia, and some yellow polyps. Recently, no matter how many water changes I do, I can't get rid of this thin layer of scum on top of the water. It wasn't there before, and if you don't look up at the surface you don't even notice it. SHould I just ignore it? Could the corals be causing this? because it definitely wasn't there until a few weeks after I started adding corals. Thanks.