Ok here goes. I have a 3 story home with a bathroom on each floor and all are above each other which I assume that means they are on a shared drain line and vent stack. Im having a devil of a time figuring out what the real issue is thats troubling the toilets. I keep thinking I have a venting issue but only as augering and snaking has been done at varying times. here's a bit o history below. I have had over the years intermittent clogging issues with the 3rd and 2nd floor toilets. They also seem to regularly slow drain. The first floor toilet seems to have consistently worked fine. The most recent issue was someone used the toilet on the 3rd floor and flushed only urine and the toilet overflowed the bowl. dafunk? what ive tried: I have had the main line (from the basement connection) cleared a month ago. I have used a toilet auger on the 3rd and 2nd-floor toilets about a month ago when they were both experiencing issues with backing up. I did have to fight a bit to get the auger thru on one of the toilets, but i was also using a bit of a cheap auger... I have filled both the 3rd and 2nd flr toilets with muriatic acid and let sit for an hour as I heard this was a good way to help with slow flow issues by clearing the water jetting area(however it didn't seem to do anything). What i haven't done in ages: I have not run a larger snake down the line from the 3rd floor toilet down to the basement personal, but i think this was done back in 2005 or so. So that should be a good start of info and hopefully, someone can point me in the right direction for me to address this or get a service tech over to take on what im not equiped to do. Thanks for any help! Note - tools I have are crappy auger - should have gotten the 40$ model. A rigid 2" snake with all the varying heads.