The double discussion was a mistake. But i have a 20g tank and I have Swordtails and neon tetras. I keep my lighting on for about 10 hours and then turn it off the rest of the time. There is Blue Green algae and there is also Brown hair algae in my filter. Usually I do water changes once a week and siphon the gravel. I also clean my filter after a water change. The algae usually comes back every week and I don't know how to permanently get rid of it.