This bottle is a complete waste of money (and I bought it on sale). After a few uses the bottle started to smell and my daughter would complain. So we took off the filter altogether and just used the bottle with water from our large Brita jug. Even so, after a day or two, the bottle would have a very strong smell. Never had this issue with NUK sipping cups or Klean Kanteen bottles and we used them in the same way. We have stopped using this bottle and bought a new KleanKanteen.