In either bathroom, when we flush the toilet, the tub gurgles, or if we drain a full tub, the toilet gurgles. In the morning(heaviest water use), we are getting stout septic odors in the end of house closest to septic exit and cleanout. I have snaked the vent behind the washing machine, and both vents on roof. I ran a garden hose down roof vents and didn't get any backup into sinks... and watched water flow through cleanout. I've snaked from cleanout up to tee under the house but it seems to flow freely. This is an aeration system on a mfg home. Less than 5yrs old. What other problems could be causing the gurgling and odor??