Sorry the photo of the Nursery water with minerals won't load but that was the culprit

That's what is was..Baby Nursery water. It started when I started using this since they were out of the distilled. Photo included

When you say filter do you mean the disposable air filter? If so... yes I do regularly. Never heard of a water filter on those so am guessing that's what you mean

My machine is a Air Sense 10 and all I clean with is mild soap no abrasive cleaners. It's not actually rust just the color of rust however it does clean off. Mabe bacteria or ? I rinse it out daily and clean with soap weekly. Thanks for your replies

Hello, my 3 week old resmed humidifier tub has what looks like small rust spots. I returned the 1st one and now it's happening again. I have always used distilled water and never had a problem with my original one. Does anyone know what the problem is?