Lately I have been waking with nasal congestion so bad that I can’t breathe. I change the filter on my Resmed 10, clean my Quatro FFM but still having this congestion. I am not allergic to anything but cats. I understand that congestion is due to partials in the air. So I wonder if there is a better filter I can add to my ASV to remove these allergens? (Assuming that is what it is). This is new the last 2 weeks. Anyone else experiencing nasal congestion ( no running nose, just stuffed up at night). I have not had a good night sleep for a while.
I don't have any advice on your filter and don't recommend trying to modify the filter. It is a good idea to regularly replace the filter (once a month). I personally use Flonase to keep my nose and sinuses clear. I have had great results. Flonase is a steroid so you should ask your doctor if it is appropriate for you. But, you can purchase it over the counter and I use it once daily 1 hour before bed. One shot in each nostril. I too have a mixed lot of allergies.
A change in the humidity settings adding more or turning off can also help congestion (But which varies from person to person)
Are you using Resmed BRAND filters? Or knockoffs? The brand name filters are much more effective, but do seem to do a good job.
Last few weeks is likely to be pollen more than anything else.
Try taking something that will help with pollen to see if this helps.
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I am NOT a doctor. I try to help, but do not take what I say as medical advice.
I am just a long term user of c.p.a.p. and therefore I have some experience in using these machines and equipment.
However, I am NOT an expert, so advice given should be taken as given in good faith only and NOT medical advice.
Every journey, however large or small starts with the first step. 
