New member here with a situation I am hoping for pointers to resolve my problem. I have lived here for twenty years, 50's low bidder built ranch house, slab floor. Until past year or so the hall toilet would nearly overflow after a flush only a couple times a year with daily use. Now several times a week it is doing same. If left alone for hour+ level has returned to normal and a flush is fine. During a trouble episode I can put about 4-5 gallons in tub and pull plug which results in water level rising in toilet and substantial gurgling and bubbling in toilet. Once tub quickly drains, it will pull most of water out of toilet. Sometimes I can flush immediately after above procedure and it will flush normally while other times will rise high and take a long while to return to normal. There is a cleanout directly behind toilet outside and I have rented a snake twice and never encountered anything. I tried to snake the vent but it must tee or something as I hit something hard about 3-4' below roof. I had a hose up there and ran a bunch of water down it. Lately we have made a habit to flush toilet before setting down and prior to flushing to open faucet in sink as flushing. Seems to make no difference. Been very frugal with 'the paperwork' Nothing seems to make a difference Master toilet has never had a problem Hall toilet tees into the straight shot from master to exit Will be immensely grateful for any ideas out there on where the problem might be lurking.