Has to be RO as DI is corrosive to pumps.
RO=Reverse Osmosis
DI=De-ionization
Shaun
Shaun, Im a pure waterfed pole window cleaner as well as a carpet cleaner.
I use RO+DI to clean windows pumped through a 100psi shurflo pump, i have used the same pump for the last 3 years and its still going strong. Pure water is corrosive if it comes in contact with untreated metal and is extremely damaging to wooden window frames.
Im not sure how pure water will be better than normal water for cleaning carpets, but I carry 650 litres on the van so i think i will try this theory on a old bit of dirty carpet i have for testing, and i will post the results here when done.
Just to let you all know its not the pure water that attacks the dirt on windows its the brush on the end of the pole that aggitates the dirt free then the pure water rinses it away leaving no water or streak marks; its called the typhoon effect.