As I posted a couple of weeks ago, I am upgrading to a 120 from a 38. Over the last couple of weeks, I have gotten the 120 temp stable and have been slowly transferring about half of my live rock from my old tank to the new one. I have also purchased an additional 75 lbs of live rock and placed in the new aquarium. Five days ago I did add one fish and he has been doing fine. I also have numerous snails and crabs in the new aquarium doing fine. Some of my old live rock of course had some polyps and trumpet coral attached and they have been doing fine. I have also been adding each day a little Biozyme for saltwater aquariums (basically live bacteria). I have tested the water every couple of days and have not seen an ammonia or nitrite spike. However, tonight I tested again and the nitrates are beginning to barely register. Does this mean it would be safe to go ahead and transfer everything else or should I wait awhile longer? The reason of concern is that some of the corals in my old 38 do not look as good. I am wondering if transferring the old live rock is having a detrimental effect on my old aquarium. Any thoughts would be greatly appreciated.