Diana K

I have it in one tank. Good for soft water fish.
I would not mix it with gravel, though. 'Gravel on the bottom' does nothing for the plants. Flourite is heavier and will sort of sink through it, though they will stay somewhat mixed. The gravel will sift up and down through it whenever it is disturbed. I have some light scatterings of gravel as decoration in some tanks, and the gravel appears and disappears as things shift around.