Thanks, little bit far(I don't travel much) but I wouldn't mind some info on how you do yours. I'll be on a meter soon so the plan is to suppliment my water with rainwater. All the 'proper' methods on the net seem to be way too expensive. I'm not sure yet if I can find a way to pass it through the resin bottles on my existing system. It might mean going back to having the resin in my van again so that my ro water and rain water mix goes through them.
I don't like the di in my van as it always gave me pressure/air lock problems.