So I run a oil-filled heater in my snake room which borders two walls (corner of the house) so its absolutely necessary for ambient temps. However my humidity is down around 20%. I have a sunpentown su4010 humidifier which can turn the room into a jungle mist, only thing is I use tap water. It does have an ion-exchange filter but thinking now to use either DI or distilled water in it. Wondering if anyone has put any thought into this, and/or had problems with running hard water in their humidifier.