Bit of an odd question here I guess, but just wondering how common it is for mold to develop inside the humidifier bay of a machine? (Not the tub, but inside the bay itself).
My mother uses a Resmed Lumis 150 VPAP-ST machine, which I believe is probably a very similar design to the Airsense 10.
A couple of days ago whilst re-filling the humidifier tub for her I went to put it back into the machine and I could see some dust sitting on the bottom of the open humidifier bay in the machine (picture below with an arrow to show where I mean), so I wiped the dust out with my finger then noticed that my finger had some black substance on it... I wiped around the bottom of the area again with another finger and sure enough, more black substance was on my finger.
To describe the substance I am talking about, it was similar to if you scribbled on a piece of paper with a regular lead pencil and then wiped across it with your finger, a similar looking residue to that, except more black in colour.
I got some tissue paper, wiped around in there and got some more of the substance, then got some more tissue paper and wet it a little with some distilled water and wiped around again but at that point there was basically none left.
So basically, I am trying to think of possibilities as to what this black substance could be, perhaps mold? Perhaps a black coating/colouring coming off the machine itself? (the inside of the machine is black in colour).
I cannot detect any sort of smell, and there doesn't seem to be any more of the substance but I will give it a week or so and wipe it out again to check if it has returned.
I do also notice some small black spots on the bottom of the humidifier tub whilst filling it up with water each day too, which I usually wipe or scratch off and haven't thought much about them, but not sure if they are related.
Are we supposed to be cleaning inside the machine itself? We have a regular cleaning process for the machine equipment (mask wiped out daily with mask wipes, mask/tubing/humidifier tub washed out weekly with vinegar/water, except for the silicone/rubber components which we wash in soap/water), but we never clean inside the actual machine itself, we just give it the odd dusting now and then.
Just wondering if anyone may have any idea what this could be, I am hoping maybe it was just some colouring coming off the machine itself and not mold!
Thank you for any assistance
Picture of the area I am referring to where the black substance was:
