Blue DMT stones are 325 grit, red are 600, green 1200, white 2200, tan 8000. Blue is medium coarse for removing smaller nicks, establishing a primary bevel. You need to go a bit finer than red and that can be done with any stone or sandpaper around 1000-1200 grit. With sandpaper, you have to pull back, not go ahead or back and forth or the paper will be cut. I prefer to use a leather strop charged with paste chrome polish after the 1200 and see no need to go to the 2200 or finer, unless you are in a sharpening contest and have an electron microscope. When working, I can usually hit the strop and renew the edge a few times. When it's time to resharpen, if the edge isn't nicked, I'll start with 1200.