SUP BUD,
Do not use that in the main tank, you'll probably end up crashing the whole thing.
Furan 2 is used mainly as a dip or for a hospital tank. Separate treatment.
I've done small rock sections with dips but not large sections to continue to have the biological aspect alive in the main rock work. So that in case the small rocks im dipping die off, I have the main rocks to seed the small rock sections. But I also wont' immediately place the small rock work in the main tank, I leave it in small hospital tank then keep rinsing it with water from main tank that I take out from WC.
Just call me if you have question man.