I have a problem with water draining. I have a septic tank installed 3 years ago. I have pictures of the plumbing as it was laid out. It started with my toilet backing up and I took the plumbing vent off the top of the toilet trap and it drained fine. I am worried about sewer gas back up now. And when I use the washing machine a frigidaire electrolux stackable, it backs up in to the tub sometimes and it almost always backs up onto the floor. I put some of that Hot Power acid down the drain and tried to snake it but couldn't find a clog. My washing machine looks like it starts into a 1 1/2" pipe then turns into a 2inch.This problem is real annoying not nowing when the toilet will backup(eventhough when I took off the vent it never backs up) but the washer still back up onto the floor. It seems like the piping is too small but it is all large piping I do have pics if it will help Please help Thanks.

When was the last time you had the septic tank cleaned and pumped?