Hey Squishy
You should be aiming for a pale pink. It will be darker pink/purple if you are dehydrated. Quick word of warning though, some people never see pink on a ketostix (me included). Ketostix only pick on one type of ketone. So don't get too worried if you don't see pink.
You'll know when you are in ketosis as you won't feel hungry, have a furry tongue/funny taste in your mouth and feel really good/full of life!!
x