I've been exterior cleaning for a few years now, mostly patios & gutters, with a few window jobs - all done trad. The window cleaning side has been picking up, and I have decided to add a WFP system to my van - as it'll help wash down windows after cleaning gutters + it'll speed up my window cleaning work. I've got some pre-filters already (sediment, carbon) which are between my tap & tank. I've been given a couple of DI vessels from someone, which I think are 4.6lt. As I'll only be using around 300 - 400 litres a week, do you think these two DI's will be enough - one before the tank, and one after? The TDS reading after the existing pre-filters is around 230ppm. Obviously I'd like to use the DI's as they were free, rather than spend extra on a RO (though I appreciate the benefits). Any advice gladly received!