Count another one for mag float. I'm not a fan of purchasing any fish for the purpose of doing "a job" but if I had to pick a living solution to an algae problem it'd have to be nerites.
I vote ottos......tireless cleaners that don't add a lot to the bioload.....I put 8 in my 55 two weeks ago and they get the glass, plants, and decor in my tank spotless. Diatoms watch out!