Saying means you are expecting the listener to do or start something in response, like "hey" or "come on". So "" would sound like you're urging someone, like "Hey, time to go to bed!" If you just want to add the nuance of "okay" or "now", /// is the correct choice.
/// is used to indicate it's time to go (back) to an important/original topic after desultory chatting, silence, greeting, etc. For example, saying "" is fine when:
1. you've been chatting with your guest for a while with a teapot in your hand
2. the tea itself is the main purpose of the gathering
But if you said it in an inappropriate situation, it would sound puzzling, and your guest might wonder if the tea has some special meaning. (/etc also means "in which case", but that's not relevant now.)