I have a 10g tank that is lighted on one side by a regular incandescent bulb and on the other side by a screw in compact flourescent that is blacked out as to only spotlight some rocks and java moss/fern at the back of the tank. At first I was getting hair algae on the spotlighted rocks and glass, but that has been replaced by brown algae and that bright green (ugly) algae. I welcomed the hair algae because it looked nice in that tank, but the other stuff is unwanted. Are there any conditions that would favor hair algae over other kinds of algae?