Take a deep breath and relax . You have to wait for mother nature and she doesn't like to be rushed. The rock that you chose unfortunately is know for a large amount of death and decay trapped inside it . It may take a little longer for the nitrogen cycle to complete . It would be almost like some trying to jump start their cycle with a pound of dead shrimp from the grocery store and waiting for the tank to reach zero . After they reach zero your nitrates will probably be very high. I would do as close to a 100% water change after the cycle is complete otherwise I see you battling high nitrates and the problems that come with that right from the gate .