It depends how much boullion you use really to make up your drink! I was having about a heaped teaspoon worth a day!
It's up to your really how much you have but as there are carbs in there just be careful, everyone's ketosis has a different sensitivity to how much carbs knock them out so it depends on your body really but try and stick to as low as possible to make sure you don't knock yourself out and make the diet harder for yourself x