Humidifier Water

I have an Airsense 10 Autoset Machine. For some reason I seem to be using more water then usual during the night. I have the Humidifier set on Auto and the Hose Temp. set at 65. I'm not using the Machine anymore hours then usual. Any ideas??

Most likely the air in your bedroom is a bit drier.
Ambient humidity is the most common reason.
Less common are pressures used and large leak.

When our ambient humidity is higher we won't use as much water to maintain humidity setting.
When our ambient humidity is lower we have to use more water to maintain the humidity setting.

That makes sense Pugsy. I don't heat the bedroom, it stays in the mid 60's, I like the cooler air. Also looking this morning I have one of those cheap Humidity/Temp. gauges in there. The readings were 64 on Temp. and 29 on the Humid., kind of dry? And lastly, I have Forced Air heat, which is notorious for being dry.

29% humidity is pretty dry.
I also have one of those cheap gadgets but they are surprisingly accurate....mine said 45% last night and 6 hours of machine use...and the tank is nearly dry...setting of 6.
When it is raining outside and window open I have seen 80%....and the machine not use much water at all...same settings.

As long as you aren't running out of water during the night and getting the stinky hot plastic smell...I wouldn't worry about it.
The worst thing is you have to add water every night which is something I have had to do pretty much all the 12 plus years I have been on cpap. The only time I haven't had to add water every night is when we have a prolonged rain and windows open.

And yes...forced air anything is notorious for drying out the air...be it heat or air conditioning.
Some people add in wood heat....and really dry out the air.