My 75G has been set up for almost a year and a half, I was told that this brown stuff was common in newer tanks....I wouldn't consider mine 'new' anymore. I still get it on the glass and fake plants....and you're right, cleaning it off only brings it back in a few days. I also get it pretty bad on the gravel itself...just days after a w/c.
I had read a couple of things on here but not yet tried it....one person a year ago maybe said real driftwood in the tank may help. And others said live plants live off this stuff..........I'm just afraid to deal with live plants....I barely keep my house plants alive.......lol
Will be interested to hear opinions on this thread......because I'm pretty tired of it myself.
Oh, someone else had told me otos are about the only guys who will eat the brown algae. I bought a few once, and they did attack that brown stuff. But they also didn't stay alive. Of course I had pictus catfish at the time....and probably wasn't a good thing for the otos.....