I am using samsung galaxy J5, 2015, (android Lollipop). I have tried several alarm clock app with "sound off, vibrate only" function. But they all have sound and vibration both when the alarm clock goes off. Does anyone know why? I already set the cell phone sound off, media sound off, and the alarm clock app individual volume sound off, but that still doesn't work. The sound and vibration still go off at the same time.