What's with the air bubbles?

[LSAT]

Often I wake up during the night and feel a few air bubbles popping in my mouth. What's that all about?
Generally I fall asleep pretty quickly but often wake up aboout 4-5AM to go to the bathroom. If I can't get back to sleep within 20-30 minutes I take off the mask.

[DreamStalker]

You are leaking your treatment out of your mouth. Some around here call it mouth breathing but more correctly it is called "mouth leaking".

Your fix options:

1) use chinstrap (doesn't work for most but try out the PAPcap if you go for chinstrap), tape your lips together at night or use polident glue to seal lips
2) find a full face mask that is comfortable and maintains a good seal
3) learn/train yourself not leak air out of you mouth (again, not everyone can do this)

You seriously need to get a machine that provides efficacy data (your listed one does not) and also invest in the appropriate software for a good machine. Ask your doc to change out your machine to an APAP (just about all APAPs provide good data and are software compatible). Do it ASAP before your rental period is over. If you have already paid full on your machine, consider getting a new one and either selling yours or keeping it as a backup/travel CPAP.