What Causes Green Algae

[crazycatfish]

I used to have a problem with brown algae but i managed to clear it and stop any more unwanted blooms.
Now i have patches of green algae on my tank walls. Why has it started to appear.

 

[evilchild]

too much light is more likely to have caused this, try cutting down the amount of light for tank is getting. try turning the light off for a bit longer see if that helps.