Well I would like to say how helpful this site is with the advent of a slightly more technical and expensive approach to window cleaning. My 40/40 has now provided two and a half years of excellent service. I run it from tap pressure here at Wymondham. The water is around 360/70 tds going in and produces water before DI at 5 TDS. I have found cycling the water softener before production makes all the difference. If I did`nt cycle the softener it would be around 45 TDS.
Thanks for all your help advice and tips.