My 50G planted tank has been set up for almost 2 years. After MANY trials and tribulations I changed 1 thing.
A little back story. I started to develop algae. It started with hair algae and developed into this glass covering green algae that was not easily removed. I did almost daily water changes; I treated with Excel (at the cost of some plants); I got flag fish but nothing worked. I decided to do Co2 so I started mixing yeast and sugar. I noticed a lot of growth on the plants but not effect on the algae. Then I finally gave up resigning myself to just scraping it at WC time. I would turn the filter off, scrape and let it settle to the bottom so I could vacuum it out.
Then about a week before Christmas I decided to re-scape. I wanted to spread out my stem plants but I couldn't put any on the left side of the tank as the HOB filter was there and the output wasn't nice to the plants even on the lowest setting. I wanted it to look more even so I put the filter in the center. This allowed me to stems on the left and right sides of the tank. I still have the yeast/sugar mix Co2. I use a regular air stone and place it next to the filter input. The most miracle part is that the algae is almost completely gone. It was covering the back wall of the tank and is clear. On plant leaves? Not any longer. I don't know why (not that I really care) but it is gone.
I am not sure if this is really due to moving the filter over but I will take it.