Sleepea

Okay, thank you. If I take a nap during the day I usually don't put water in the tank.

I get 0 often enough, and readings under 1.0 most of the time. The machine is in CPAP mode.

If I don't use the CPAP I will snore, and wake up with headaches. If I do use it, I have low readings.

It might be time to get a new machine.

If you are good with repairing electronics, and can find the part number for the defective part you can search for that. If you can't fix it yourself I don't know.
Some people won't fix medical equipment, but your laws may vary.

Ask your doctor to look at the data on the machine. You might not have a high enough pressure.

What brand of machine do you use?

What CPAP did you say you use? How do you turn the humidifier off?
With my old F&P, the airplane mode turned off the humidifier, with the AirSense 10 the water basin still gets warm, and the heat indicator lights on the display in Airplane mode.

Any of the searching I have done on this shows that it has been a long-standing problem. The sensor probably wears out.

The old topics on this same problem https://myapnea.org/forum/cpap-machine-won-t-shut-off-part-deux

I am wondering if it is because of a software update.

I use Fisher & Paykel masks, they come with a cloth or cotton defuser. I disliked the Resmed masks because of the open vents,

Jeremy, My CPAP machine, AirSense 10, has a small air filter built in. It isn't HEPA but it helps reduce some garbage before it gets to the machine. I did notice that the filter on my last machine wasn't as dirty after I started using the Honeywell air filter. The reason why the prices have increased is supply and demand, with COVID more air filters are selling, prices go up. It is winter in the Northern Hemisphere as well, and when people are stuck in doors people worry more about air quality.

tallullahjo (I don't know if you have returned to the forums) An article about different air purifiers. I don't trust most "best of" articles on any item, there are many and each article produces different results. If there was any science behind the article there would be one or two devices across all articles that stand above the others. However, knowledge is power, getting as much information as possible is helpful. https://www.thegoodtrade.com/features/best-home-air-purifier

You can always make your own. (This is my friend from the above comment) He has several air filters.

https://www.youtube.com/watch?v=zaauMVWxcp8

I made one of these filters as well.