When we are running the washing machine we are getting large air bubbles coming up through the toilet. I live in a 2001 modular home and the septic tank is at the other end of the house. I have not had anything done to the septic tank since we moved in. New house and septic. We treat the septic once a month with rid-x, is it time to have the septic pumped. Could I have other problems? Any help would be appreciated.