Got a 70-'s era 2-story house, two toilets share a stack, one upstairs, one down. The upstairs one does not flush fully with any consistency, I mean to say the bowl doesn't really exchange a full load of fresh for what's sent down. Worse, the downstairs toilet on the first floor tends to clog for no obvious reason, at unpredictable times, and it also runs slow when flushed. I suspect insufficient vaccum break by a clogged vent stack, but I'm afraid of hieghts to go up and check, plus, I don't really know HOw. I read something about a length of chain on some rope, dangled and sort of swished around, to clear any old bird nests or whatever that may be clogging the vent stack... Any real plumbers have better advice/ observations? TIA.
msu1049321atayohelldotcom.