Yeah, I figured the shut off out. If you pull up the tab on the top, it shuts both lines off.
As far as bubble, mine starts off with air for a few days after opening it up or replacing media. I can get more bubbles/air if I shake it but only when I shake it. Mine does have a small hum but no where near as loud as my whisper 30/60. My air pump is also louder. I did have a friend that had issues with air and louder operation but quickly discovered that she had put it too close to her air bubbler and was being drawn into the system. I still love mine and hope to buy another one soon.