Sound advice, glad it was you and not me who figured that one out.
I go with about 1/2 packet of the Propel powder in a 20oz water bottle, about 1/3 packet in my 16oz Polar bottle. I tried a whole packet in a 17oz bottle once, like the directions say, and it was so sweet I gagged.
I won't ever put that stuff in my Camelback, though.