Help...Fishtank!!!! Algae everywhere?

Hey my fish tank is gaining algea like none other and I have tried almost every trick in the book. I have an electric catfish in my tank so I can't add any other fish really. I have a planted tank aswell. But the algae on the tank is getting really bad and I don't know what to do to keep it under control. My phosphate levels are fine so its not that. and I tried turning off the light a little earlier every night but it hasn't done anything for the algae but the plants in my tank have been suffering. Please help