I've got a 55 gallon that I can't seem to rid of algea, I've gone to the extent of covering it with a sheet for a week and a half so no light got in. The fish were moved so I could try to get it under control. Its green and seems to begin to form in small 'puddles' on the tank floor. Its a bare bottom right now, it was a tiled bottom. nitrate <3, nitrite 0, ammonia 0, gh 100, kh 120, ph 7.5.. Aquaclear110, and Marineland 350bio wheel. Light is down to a minimum, I'm not feeding, theres no fish in it. It was cycled prior and has been set up for 3-4 months. Every time I vacuum the algae up it returns the next day, can anybody help me? The algae forms in a line directly under the filters and runs the length of the tank. Its very frustrating.

