Vents pluged. That why you can hear the glug glug sound, it's creating a suction.
Take straw and suck up some water in it, now put your finger over the tip of it and pull it out. What happens?
That would be my first guess.
PS Never use a drain cleaner!
Take straw and suck up some water in it, now put your finger over the tip of it and pull it out. What happens?
That would be my first guess.
PS Never use a drain cleaner!