Yeah the bulbs or water flow are usually the issue, if all other perimeters are good. The refuge with macro shouldn't cause cyno to grow because the macro and cyno are fighting for the same nutrients. I would venture to say that if you have lots of fish, perhaps overfeeding could also be an issue and the food and waste depositing in that area. A small powerhead with flow directing in that area should do the trick. Without looking at the tank hard to say but keep us posted.