[Inside Out]

Isn't the DI process what repels dirt for while, meaning cleaner Windows for longer, meaning custies are happier, and tell all their friends and family to use you cos trad just doesn't give results anywhere near as brilliant!!?

[StockClean]

Erm i dont let my tds levels go higher than 000

i have taken many jobs off of other window cleaners who dont keep on top of their resin changes.

Many customer who had been used to window cleaners not using pure water to wash their windows had lost faith in wfp method due to spots.

I have to say i never have problems with spots and all my customers always seem happy with the results.

[PureClean Window Cleaning Ltd]

Heres a quote from www.clearviewplus.com which i thought was interesting

While this rain water is no longer pure, it does have a relatively low mineral content. In the UK with our usual south westerly winds, the total dissolved solids reading of this water is around 14 TDS, with the limit for spot free drying being 9 TDS or lower. (Some tap supplies will reach 500+ TDS)

When cleaning windows with pure water, pure water is left to dry naturally on the glazing, when the rain comes into contact with this water, it serves to dilute the rain water. If an equal amount of rain water falls on the freshly washed glazing, the TDS reading of that water will then read 7 TDS within the range of spot free cleaning.

im going to stay with resin though, just for peace of mind,

[Inside Out]

But if you get twice as much rain your screwed anyway right? So why bother 
This must be what customers mean when they say"not today please cos we are due some dirty rain" I hate that!

[richard jagger]

Dirty rain: is rain carrying dust from the Sahara desert carried very high out in the Atlantic and turned around by low pressure belt and depositing the sand in the U K as sandy rain and can be seen on a cars as muddy rain drips.
A  D I unit also alters the polarity of your pure water so will remove negative and positive charged dirtwhich other water will not.

[dazmond]

000 for me every time if possible.if your a professional wfp window cleaner then its the most basic thing you get right!

why take the risk?keep it at 000.remember if your tds is higher than 000 then you run the risk of more spotting!

and none of us want that!!

[richard jagger]

All TDs  are not the same if eg. you have a TdS of ten and all the parts were derived from the same chemical I could understand these arguments but unfortunately there are no.If all the 10 parts of the tds is chlorine.You will see nothing on the glass. If all the tens parts are derived from lime you could wipe them off and if all ten were iron bases and heavy metals you would battle to remove them .AS I have said before every thing in chemistry and TDS are not always equal. Same tds parts are de-solved some are in an emulsion and some is solution some are gasses. Its not that simple guys. 
That is the reason some guys can clean with 15 and even twenty and get away with it and some guys have spotting at 7/8.

[Jeff Brimble]

Dirty rain: is rain carrying dust from the Sahara desert carried very high out in the Atlantic and turned around by low pressure belt and depositing the sand in the U K as sandy rain and can be seen on a cars as muddy rain drips.
A  D I unit also alters the polarity of your pure water so will remove negative and positive charged dirtwhich other water will not.

Could you expand on the bit about the change of polarity please ?