I understand about the colours supposedly meaning about dehydration and stuff - but when I did Atkins, we were told in the book to get ketostix - and the darker the colour the better, because it measures the ketones in your urine - and the more there are, the more fat you are getting rid of.
Since starting LL, i've tried to keep it paler, but it's always quite dark - and no, I don't drink much water (max 3l)... but it was always practically black when I was on Atkins and I lost a ton of weight and felt great. I wouldn't take too much notice... as long as you ARE drinking enough water, which is important regardless of how it affects the stick.
Anna x