This is a really gross humidifier question...

The other day I had given my husband a ten-foot hose I don't use (I started using a heated one shortly after starting cpap). I kept finding him with the mask on, machine running, and the hose halfway disconnected from his machine at the back, so I finally convinced him to take the longer hose. He said he couldn't get it connected. When I went to connect it I removed the humidifier so I wouldn't accidentally get water in the machine while moving the machine around to connect the hose. When I pulled it out, man, talk about gross! There was a layer of beige stuff all on the inside, caked on almost like concrete! He never cleans it and he always uses tap water. (He knows better, because I've told him often that he needs to clean it and to use distilled water; he just doesn't want to.)

I was able to get most of it out by scraping and chipping away at it, but what is that beige concrete-like stuff anyway...mineral deposits from the tap water or something more harmful?

Not that anyone here would have this issue to this degree, but just a major warning of what can happen if you severely neglect proper care of your humidifier!!!

Likely mineral deposits. I would just replace the water chamber. It doesn't hurt to do that once in a while anyway.

Sounds like you might want to replace it more often if he doesn't want to clean it or use distiller water. Mold etc can grow in it, which isn't good...

A good soak with a strong solution of vinegar and water should clean up that crud pretty easily.
I had a machine that I used for travel only and I never bothered with distilled water. Saw a bit of mineral build up starting so I used some vinegar and it came off really easily. Now we are talking about may a total of 14 nights with tap water so the build up wasn't huge and I could really only barely see it.
So didn't take long to clean it right up. For something with heavy build up might take a couple of longer soakings.

You can also buy a replacement tank.

I use distilled water in my regular machine and no build up at all.

Thanks for the suggestions! I'm going to try that solution, Pugsy, and hopefully get anything that's left over. Unfortunately he thinks it's ridiculous to buy another humidifier, which was what I wanted to do when I initially saw how horrible it was.

I've been on cpap for a little over five years now (he's been on about 2-1/2). There are only a few days a year when I use tap water, the rest distilled, and I still have my original humidifier. Never have had any type of crud in it at all. I also clean it, but only once a week. (He also rarely changes his filters... ).