Demin water is just what it sounds like ... all of the minerals have been taken out usually through reverse osmosis (RO).
Distilled water has been boiled and then condensed back to water in a separate container.
Difference is distilled water also tends to drive off any chemicals (chlorine) in the water also which can pass through an RO membrane.
Most bottle water we drink is Demin while Distilled should be available at your local Walmart.
Demin would probably be just fine to give you the short answer to your question.
