I've had a thought, ok i know thats dangerous !!
But what Dave said about the clear finish on dishes /glasses got me thinking. I havn't got a dishwasher, i do mine in the sink and my glasses still come out perfect.
When i looked on Google at what it actually means/ does when the water tension breaks down well you can see the difference by dropping a paperclip in a glass of water. Plain water the clip floats, water with something in it to break the surface tension and the clip sinks . Apply that to dirt instead of a paperclip ? I know most of the dirt we take off is water soluble but how would less water tension affect that ?
I'm gonna try adding a bit to some plain old tap water and see the results. We might all be conned into buying RO's that we don't need ?