My fishtank is over exaggerating on brown algae!!!?

i have a giant rock plastic and its covered in brown algae,my sand i clean all of the brown off and the next day its back twice as big? should i get rid of the live rocks i have only a majority of the live rock is brown the other might get contaminated if i do not. i only have a eel and i use florescent lighting, even my plastic boat is getting covered in brown algae, what type of rock should i get or purchase that brown algae wont grow on,its a 55G i do my water changes my calcium and other suplements are awsome thier doing great, but my Coralline still wont grow its such a bummer i tried everything i learned to try to make Coraline grow.