Another really good question. If you used the original sand or gravel or whatever you have then that is also I;d say the most likely source of ammonia. Moving a tank and not using new sand can muck up all the nasty crap in the sand and cause massive spikes. A good sized water change, like 50g would be a good place to start.
make sure the temp, salinity and ph are as close as you can get them so you dont shock what you have in the tank.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.