Lately I've been having a problem keeping the humidifier reservoir clean. I soak and clean it with a little Dawn dish soap in warm water, and every so often in the dishwasher. I only ever use it with distilled water. The next evening I look in it and see stuff(?) in the water. There is also grime on the heater plate - especially visible if you touch it.
The first time this happened I cleaned it and changed the filter, but it was back the next day. I'm also using one of the thin white filters with the dark grey foam one that fits in the recess on the back of the unit.
I've also removed and cleaned the round silicone seal that fits in the lid that closes on the top of the reservoir as well as the ones that seal the reservoir to the unit.
I have a small flashlight with a 24 LED floodlight on the side (it's really bright) - the face is about the size of a credit card. I hold it up against the side of the tank in the dark and anything in there is very visible.
The seal between the halves of the reservoir are ok and I'm pretty sure there are no cracks. When I hold it sideways with water in it, if there were cracks or any part of the seal was bad, it'd leak, and it doesn't. I think the seals are silicon and should probably outlast the machine.
The top pic here is before use, filled to the line, and the second one is the next morning (I forgot to put the black piece of plastic under it in the 2nd pic).
Any thoughts as to what that stuff is or anybody have a cure?
Note: When posting this I haven't been with ApneaBoard long enough to post images or links. If the pics don't show up, just add in the http stuff and get rid of the space.
Update: Yesterday I soaked it in warm water and a little Dawn for about an hour, and then into the dishwasher it went. The top pic was after it dried out, and the bottom one is from the next morning: