My tank is a 65 gallon heavily planted all flourite substrate....I would recommend 100% flourite because if you mix it with something else, you will never be able to get rid of the other substrate if you want to go all flourite in the future.
IF you want to add colour, there is flourite red that you can mix with your regular flourite.
I am assuming that if you are going for a flourite substrate, that you want a nice planted tank.....for me, i have so much plants that I can barely see the substrate anyways, except for the front but flourite looks so natural and beautiful anyways...