I got my 20 gal tank 8 wks ago. I have a test kit: My Ammonia is sitting at 1ppm, Nitrite 0ppm and Nitrate between 10/20ppm. 3 wks after I got it I had nitrites of .25 and then it disappeared. I do a PWC 2 times a week, just changing the water not doing anything to the gravel. My water temp is betwen 79-80 degrees. I use Prime every other day and when I do a PWC. Not sure what else to do to finish cycling the tank