Magnesium has been proven time and time again to remove this stuff, and I have had good success with it; unfortunately, one needs to be careful with this method if zoos are in the tank, as some lose their colors with the high bump of MG in the tank, and some never recover their original color; I learned this when I went through an outbreak of this stuff myself. There really is no way to remove it by hand, because it grows back way too quickly.
It is a nuisance thing that should be removed as soon as possible.