I use the ketone sticks as well. check what your bottle says, there should be amounts noted with each color change.
white=neg or 0
pale pink=trace or 0.5 mmol/l
light pink= small or 1.5
dark pink=moderate or 4.0
light purple=large or 8.0
dark purple=16

if you are finding yourself in the dark purple region you are spilling too much ketones, and your body may be thinking its in starvation mode s is holding onto calories and if you are diabetic this isn't safe. They say a safe fat burning zone is 1.5-4.0 mmol/l. All this information is in the ketone strip insert.