Hi all, Every now and again i clean the lower windows at the front of house just so i can see for myself how they dry I did this today and left them to dry, once they were dry i noticed that the kitchen window had a few chalky like runs on it so I got my pole out again and gave it another good scrub and rinse and again left it to dry???? once it had dried it was actually 100% worse??? I tested my water inside the tank and actually coming out off the brush and both have a TDS reading of 000. This has happened on a few occasions and I really cant figure it out?? I have taken some pictures and can put them on if required? My worst fear is that this is also happening to customers windows? The other windows on my house seem to dry and clean fine except for the occasional small run.