Broken photo periods might help you out. Don't know the mechanism of how this works, but it does.

Maybe 4 on, 2 off, 4 on again off for the night. Something about disrupting the photo period is really bad for algae and the plants dont seem to mind that much. Timers would work great for this.

But, I've never tried it, so I can't tell you from experience. Just something I read on the forum.