On Schedule is an organic product but it is not registered with OMRI. On Schedule is classified as a natural product with little preservatives in its formula.
Mix up only as much On Schedule as you will need for your application. Use what you have in 8-12 hours.
The upgrade formula of On Schedule is a much more densely rich brown, almost black to the eye. The older formula was a reddish brown, much less dense in viscosity. The newer formula was being Beta tested before the original formula was released. Large scale growers need concentrated products to be economically successful and Flying Skull delivered big time with the new upgrade formula of On Schedule. The new formula can be used in both leaf feed and root feed. The older formula could only be used as a leaf feed. So to answer your question without further foundation, it is a darker color mostly because it is far more concentrated.
The On Schedule was formulated to do two distinct things.
1: Push the plant into flower at will. This is important if you are an outdoor grower and adverse weather patterns show a probable short fall and the risk of powdery mildew in a damp environment. Indoor growers will see a reduction of time to get bud set and speed up development. This can take as much as two weeks off of a grow cycle.
2: Increase the flower size, flower count and oil production. Once you use On Schedule you will never not use it.