Several years ago my in-laws new aerated system was slammed at Thanksgiving. It didn't back up, but it was slow, and the water it sprayed smelled bad, which it shouldn't. Knowing that I have a little experience with poop, he asked me what to do. I told him to take a gallon jug to a nearby sewer plant and ask for a gallon of return activated sludge, or RAS. They'll know what you mean, and usually are more than happy to help out. RAS is full of the beneficial bacteria that break down unstable organic matter. Pour it in your toilet and flush two or three times and you have seeded your system with a boost of bugs. Do this about a week before Thanksgiving, Christmas, or any other big get together and your bacteria population will be ready to take up the slack. It won't help with roots or busted tanks, but will help prevent the tanks from getting too full of solids and backing up.