Hello all. Went to visit family over the weekend and they are having sink issues. It won’t drain at all. First thing I did was dump 2 big pots of hot water as sometimes the pressure pushes though. Didn’t work. I then used a plunger and that didn’t work. So in the pictures the black curved pipe is rubber so I opened that drained the water. The disposal which is gross btw doesn’t seem to be the source. After it was drained I took some of the heavy drain cleaner and poured it down after pipe was sealed. Put water back in and it filled up again but this time drained slowly. Should I buy more grease remover and pour it again or should I get an auger and go in where the black pipe is? Not very experienced at this so any tips would be appreciated