| Black Algae Problem
I have a 55 gallon aquarium home to (4) clawed frogs, (1) clown loach, (1) Blue Gourami, (1) Pleco. Don't worry they get along ok and the frogs can't eat the fish since they are too big. Anyway, I feed them once a day and leave the light on for 12 hrs. I do biweekly 20-30% water changes and 30% monthly water and filter changes since I realize the frogs expell much waste. If I am paying this much attention to keeping the tank clean then why am I experiencing so much black algae growth on the plastic plants? | 
