Depending on how big the rock is and how big your tank is, the cycle may only take a couple of days. Check your levels. I had an ammo spike in a day, a nit spike a day later and nothing the day after that. I had cleaners (snails, crabs in there in a couple of days. If the tank is totally new, that stuff is probably all going to die off anyway and your rock will probably turn kind of white and you'll get a serious brown algae bloom... It's normal, don't get worried.