algae in the tank

my tank has been running for about 3 years, and its been pretty good. im starting to notice though, that i cant grow large leafed plants (like broad swords) without having algae grow over them and killing the plant off.

how many hours should i have the lights on for? and how can i reduce algae growth in my tank without adding that 'algae clear' stuff? i dont overfeed my fish and im pretty fastidious about my water changes, so whats wrong?

 

I am not a pro on algae but you can decrease it by limiting its (tank) exposure to the sun (don't know how long) or you could get a fish that eats algae like an oto (probaly one of the best).