Beard algae is usually caused by low co2 conditions if I am not mistaken. Maybe Mathas can confirm. The best way to deal with it would be a combo of the above mentioned.
Removal of the affected leaves or at least the most heavily affected. I would also spot treat with excel. You can do this by turning off your filter to slow water movement and use a medicine syringe to shoot the excel onto the affected leaves. Wait several minutes before turning on the filter to allow contact time. If you can pull the plants out and spot treat out of the tank it is even more effective.
I am not a big fan of the idea of overdosing this stuff as it is a disinfectant (also used in hospitals) I havent tried and others I have read have had no issues doing it, I prefer to limit the amount of chemicals in the tank when possible.
Long term it will likely be back if the core problem isnt addressed.
DIY Co2 or dosing regularly with Excel instead would help. I didnt see how much and how long your light was on but 8-10 hours is plenty and should help keep algae away.