Regardless, I used acouple magnets on either side, which helped correct tilts from the horizontal, and sometimes they acted to assist centering between the carbon layers. It was definately easier to float neodymium magnets overall. I even floated the little Radio Shack Cat No. 64-1895 neo disk quite easily over these rods. There may be explanations, I think the rods were more diamagnetic than my smooth surface carbon brushes.
Water is diamagnetic.