As most of u probably know by now I got 2 little albino bristlenose plecos yesterday. Im going to put 1 in the 46 gallon and 1 in the 29 gallon and then maybe move him into the 125 gallon when he gets bigger, will they eat the algae that grows on the live plants?

That would probably depend on what kind of algae you have. As far as I know, most plecos wont touch brown algae.

well I have both, green and brown

They will most likely take care of the green, as well as some of the brown that may be mixed in. Recently, someone had given me a 9 inch common pleco to put in my 46g tank. I came home from work one day and he was in the tank. He managed to clean the entire back wall of the tank (covered in brown and green algae) before I had to give him away for attacking a couple of my commons.

maybe they'll eat some of the brown, i do have mostly brown algae but there is some green mixed in lol