I have a 5 gallon tank with a betta and the tank is full of brown algae. I've read online that this type of algea can be because of not enough light so i started leaving the tank's light on longer, and tried my best to clean it when doing water changes but the algea comes back the next day. All of the levels on the tank are good no nitrates and nitrites, no amonia. The algae cover the glass, decor and all of the gravel. How do i get rid of this algae?