I have never cleaned for anyone with a granite floor...only countertops. But I make a homemade cleaner I put in a spray bottle that you may want to try. Its safe for marble too! I combine 2 cups water, 1/2 cup rubbing alcohol, 8 drops Dawn dish soap ( you can use Castille soap if you prefer) and about 4 drops of essential oil that smells good to you. You can use a microfiber mop and just spray the floor as you go or if its a large space then use a bucket but just increase amount of water, etc. Good luck!