ok... I have about 2wpg (96w for 46g tank) and I'm running DIY CO2. I seem to be getting a little hair algae - not a bunch, but a little.
Water params aren't totally out of whack - I think they're around Am 0, nitrite 0 , nitrate 10-20, phos. 1-2, last time I checked the CO2 was around 20ppm...