I know, I know, another algae question. It seems like I get dark green algae on my floating dock a lot. It's gotten to the point that I can't get it all scrubbed off. I'm ready to give up and buy another one. And I get a weird brown film-y type algae on the bottom of the tank and on the heater. I also have green algae in the filter.
I clean and change the water about ever 1 1/2 - 2 weeks. And I scrub it down. It's a 20 gallon tank. Am I doing something wrong? It's not near a window. And I do admit that I don't clean out Filbert's poop. I just never see it!

