After a certain amount of time, most plants will not benefit from additional lighting, and the excess lighting period can certainly promote algae growth. Most folks this forum seem to use between 8-12 of light, so I went with 10 hours for my tank.
Yes, too long a photoperiod will definitely have an effect on algae! If you have stem plants, you can see them 'closing up' after a certain amount of time. I see this in my Rotalas, and aromaticas after 9 hours. My photoperiod is 10hrs.