Good point Don, wiping the tank down with Novus or Brilliantize prior to running the magnet is a good idea. It puts a "glaze" on the acrylic that makes it more slippery and removes static. Its not wax but some sort of polymer I think.
As far as the magnets, I like Algae Free's the best. The pads are easy to replace and don't scratch (unless you get something on it like gravel). On the outside of the tank I also use 100% cotton diapers that have been washed several times to make them softer. Mag floats work well but if you don't wrap them inside and out you will scratch the heck out of your tank. I have one that I use a media bag on the inside and a diaper on the outside. Both Eric at the Sharkreef and Mario at OceanReef use mag floats with the same set-up. (media bags and cotton cloth)
Just as a side note and a word of caution, Algae Free does have some very powerful magnets, especially on the Great White, they are not kidding when they say to never let the magnets attach together without a (thick) piece of something between them. I have one at the shop that is stuck together from a customer and I have put it in the vice and used a pipe wrench to try and pop it free. I all most pulled the bench over and the magnets have not moved.
