dark green algae on tank

[vivaboy76]

in my planted discus tank, i come across very dark green algae on the tank...what does this indicate??too much nitrate??

[Navanod]

I'm afraid there's no straight forward answers like pinning the cause on nitrate alone.
Too much light, too little CO2 and too little plant mass is the usual cause. Also, some green algae in the tank cannot be avoided as long as you're using a light

[nononame]

High bioload can result in algae blooms as well.