Ok, thanks! I just tested and my nitrates have spiked! They spiked to 80 or 160ppm (Using API, hard to tell the difference). My nitrite is a 1ppm, and my ammonia is at .25ppm. From what I gathered here, I wait till the ammonia and nitrites drop to zero on their own, then d a 50% water change to get rid of nitrates, and then I am ready for a clean up crew. I am doing a goby tank and was told that I have to add all of them at once, and adding the clean up crew would help the bio filter adjust, so that I would not kill it after adding fish. Is this correct? Thanks for your guys' help. You definetly made this smoother.