everything is right on as far as ph, ammonia, nitrite, and nitrate goes. still have what appears to be tiny bubbles. fish are healthy as i continue to do 20 to 30 % water change every three to 4 days. if I do not my nitrate levels spike up. plan on in two weeks taking things out of my tank one thing at a time including my my floor of peeble river rock. any new ideas my other two tanks are doing great.