One thing to try would be get a temp/humidity indcator thing from Walmart for $8. Made by Acurite.
Set that up in your bedroom.
It displays current temp/humidity as well as high/lows during the last 24hrs. Nice to know.
Specially in summer.
My guess is that, being winter you are getting super low humidity and that is messing with you.
This cheap device will verify that.
If you have tried everything else you can always get a second heated humidifier like Fischer & Paykal makes.
This will cost you some $$ and be more maintence chores, but you can get a short section of CPAP hose and connect it in *series* with your current CPAP, effectively giving you two stages of humidification.
Then you can adjust your S9 up or down from there to taste.
"With ordinary talent and extraordinary perseverance, all things are attainable." - Thomas Foxwell Buxton
I'm assuming you are using a "ClimateLine" hose and have "Climate Control" set to "Auto" if "Climate Control" shows 83 (83 degrees F). This means that the humidifier is set to provide maximum humidity while reliably preventing rain-out in the hose while the hose interior wall is heated to 83 deg. You can increase the humidity by increasing the temp. on the hose. The hose temp. can be increased up to 86 deg. F, but at 86 deg. you might run out of water after 6 or 7 hours (more or less depending on the humidity of the ambient air in your room). I would suggest incremental increases in temp. until you find a comfortable setting.
The suggestion above is assuming the H5i and ClimateLine are not malfunctioning. It doesn't sound like a malfunction because about half of a tank of water sounds about right for 83 deg hose and pressure avg. of about 10 for a normal amount of sleep time in a cool dry room; but, just to be sure, has the water chamber always been half full in the morning, or is this something that has just been happening since you have been drying out? If you are now using less water, then your "ClimateLine" may not be heating properly now and this would cause the machine to decrease humidity to prevent rain-out. How long has it been since you have replaced the ClimateLine? Many recommend replacing the ClimateLine every 3 - 6 months; but most find they will last much, much longer with periodic sanitization.
It sounds like you need more humidification.
Apnea Board Moderator
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
You could be leaking air out of your mouth. Check your leak with SleepyHead or ResScan.
Try turning off climate control and cranking the humidity up. Or use an unheated hose. You might get some rainout, but at least you'll know the machine is doing what it can.
Get the free SleepyHead software here
for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.