Long photo periods are the #1 cause for algae blooms IMO, sudden increases in photoperiod or WPG are the #2 cause, again IMO. I just cleared one up myself. I was trying to grow green algae on my rocks, and I just added another light, had lights on for 16 hours per day. In a matter of days my water was really murky. I had to dose with Coppersafe for a parastie problem. I cut my lighting back to 8 hours, and only used one light. It was gone in about a week. However if you are not using copper, you can rid yourself of bloom algae by keeping the lights off for about a week, and keeping the tank covered so it gets no light. (move your plants to another tank or container that gets some light). Perform a 25% water change every 2 days, as the dying algae will really pollute your water. I would limit photoperiods to 12hrs. Remember, plants can consume nutrients in the dark and algae can't, so longer photperiods only benefit algae.
