How do I get paint off my basement floor that is peeling and what kind of paint should I use to repaint it?

My basement floor had a gray epoxy paint over it and I painted over that with primer and a latex paint which is now peeling. I have scd some if it off but it seems like it will take hours and hours to get it all off. Is there an easier way to do this without sanding it? Also, is there a way to paint over the epoxy that will stick or a really good primer I could use; again without having to sand it?