Alright, i just set up a new 37 gallon tank about a week and a half ago (12/7). I bought about 65 lbs of rock, some live some base, and i also thru in a giant shrimp from the deli. i tested my water a few times durring the week and my Nitrates were through the roof (100ppm+). As of right now, my nitrates are reading below 5ppm. how is this possible? i havnt even done a single water change. could my tank be fully cycled already?