I have a small pleco in a 29 gal and the brown algae is outa-control so I would try the Oto or something else.
I had a really bad brown algae problem in my 65G arcylic tank. A LFS suggested an "Orange Pleco". Two days later he cleaned up 4 driftwoods and the tank. Two days after that all the plants were clean.
The LFS called it an "Orange Pleco" I have looked online and have not found anything about it. Seems all the pics I can find of "Orange" or "Mango" pleco's look very different than the one I have so I am not really sure what type of Pleco it is, But the entire body is an orange color and it's eyes are a meduim brown.
hey, this is a shot in the dark, but i'll take a stab at identifying the pleco
http://www.liveaquaria.com/product/prod_Display.cfm?pCatId=1000
i am probably wrong, but i thought i would give it a shot. i have a very unusual pleco myself and i found this site to be helpful with trying to ID him:
http://www.jjphoto.dk/fish_archive/mall2.htm
best of luck dude.