Flourish Excel works great for me on BB algae but doesn't seem to phase my other algae so I only use it when I spot some BBA growing. It seems that lots of vigorous plant growth is what really keeps the algae in check. My lights are on way longer than 8 hours, like 12 or 14.
Algae likes nitrogen, plants like nitrogen. They absorb ammonia from the water to get it and I think the plants must outcompete the algae and they both suck it up faster than nitrifying bacteria. Algae also like phosphorus a lot. Watch out for sources of ammonia or phosphorus such as ph stabilizers (phosphates) and overfeeding.
Maybe if your tank was more heavily planted that would help.