I know what fcw3269 is talkin about as far as the heat settings. Every machine will perform differently, and the way i look at it, and this is all in my humble opinion, welding is more feel than science. If your using 7018 you really dont have to worry much about slag, as long as you have your heat ...

I agree with brian, your root pass should be hotter. Tho i would leave a land as to give the hotter root pass somthing to eat on its journey to becoming a complete weld.