Demineralized & deionized water

Hi,
I am in Australia and they don't sell distilled water. But you can find "demineralized water" in the household products isle, called ironing water, however on the ingredients list it says it is "deionized water".
I'm guessing demineralized water would be okay to mix with mms, but deionized not okay as it still contains minerals. But who knows what this is....
Any thoughts?