I have a 180l plannted tank with 2 angelfish, 5 columbian teras, 3 bristelnose plecos, 1 gourami and a pair of appistogrma. I had a black beard algae problem a couple of weeks back and I used hydrogen peroxide to get rid of most of it. Now they are coming back and I don't know why? Is there a nutrient imbalance or is something lacking from the tank. There is very little flow in the thank could that be the reason why?