Well let me start off by saying this is a new tank, its 300gal. As of a month ago, I had everything to get the tank started up except for my substrate. I figured that it would show up within a day to two so I started everything thing up (pumps, heaters, ATO, etc...) and I even used the bacteria in the bottle just to jump start it some. Well, a few weeks went by and no substrate and then finally it showed up two weeks ago. So I put it in and started to monitor my ammonia, nitrites, and nitrates and all were at zero except the nitrates which were just above 0ppm but below 5ppm (I do use RO water and have periodically tested to make sure all Ammonia/Nitrates/Nitrites are at zero with a neutral Ph). A week ago, I added 3 damselfish that were rejects from the LFS that they couldn't sell and were going to get rid of because the had physical damage to them. So I figured I'd atleast give them a chance and I tested the water every day since I added them and the only thing I can get to go above zero is my nitrates and even then they are below 5ppm. So my question is, could my tank have cycled during that unmonitored period while I was waiting for my substrate? I would have thought it would have taken a lot longer.