Buying Used Live Rock

Your right, thats all you can do. and dont worry it will come, mine was fine for about 2 days, then the spike started. I too was in a hard spot since the guy we bought the tank from said the fish would be gone but werent and we were stuck with them, they were tough guys tho and lasted through the cycle, it was painful to watch. Since then we have gotten a qt tank and so on. To avoid any such thing again. Best of Luck, and when it does start the cycle, just let it run its course, i did add some dr tims one and only, to help speed things up and bring more bacteria into the mix, other then that took about 2 weeks for the ammonia to drop to zero and about another 2 weeks for the nitrate to completely drop. Do not add any fish during this time, esp a damsel or anything you do not want in there for good, since with the live rock in there they will be really hard to catch.