I put the distilled water in the humidifier every night and in the morning it doesn't seem like it's gone down at all. Is this because I haven't needed it during the night?
Is the heat turned on for it? If not, it's not going to go down much if any. This is called cold passover and isn't really effective at getting moisture into the air that you are breathing. Make sure the heat is on.
Do I need to empty it each morning and put in fresh each night?
Yes. (when the water is warmed) It creates a warm, dark, and wet environment for stuff to grow. It is highly advisable to dump it and start with fresh water every use.
It seems like when I lay down I'm getting too much air and it makes me catch my breath. Do I have something set too high.
To answer this effectively (and accurately) I would have to look at the raw data from your study. It's always possible that you are on too much pressure. You can download SleepyHead and take a look at your data and see what is happening throughout the night. This would give you some clues about the pressure setting. You can also call your doctor and mention this and ask if there is another lower pressure that appears to be effective that you could try.
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