Since your rock was previously used in another tank, and was only out of the water for a couple hours you will likely get very little cycle, and it may be over in just a few days.
Since you are very new to this hobby if you answer some questions and post a photo of your tank we can you get off on the right foot.
What are the current water parameters? (ammonia, nitrite, nitrate, pH, temperature, salinity)
What brand of test kits are you using? How old are they?
Are you using a float arm hydrometer or a refractometer to test salinity?
How often do you test salinity?
Is the sand new or did you get that from another reefer too?
What kind of fish, corals, and critters would you like to keep in your tank?