[JSMC]

so how you remove these marks ?

i havnt! they wont come off  i think i will need to use my hard water stain remover in the end

i have that MDR but trie dit once a while back and it was useless

[bobby p]

ive only seen hard water marks on 1 window that comes to mind,it was a lower window  and i realized my scraper might take it off because my scraper made a  rasping noise as it went over the marks.

wetting the window ,i now couldnt now see the marks to know exactly where to scrape  but by carefully scraping the area until i could hear no rasping noise  i knew the window was then free of them. i had the scraper at a tad steeper angle than normal,and  was taking great care . i did this window as an experiment and the homeowner never knew anything about it but if it was a paying job,i most likely would try limescale remover firstly.

 ive no idea how the window originally got the marks,they were there long before i came there ,probably they got there by the other theories posted on this thread ,such as many years of rain spattering off a dirty sill that had lime on it .

[GB Window Cleaning]

You have created the dirty/hard water via the pure  and not rinsed it off properly,allowing it to collect at the bottom. Simple as that.

thanks sean, this is also the conlusion im coming to at the minute! unless anyone else as got any ideas?

but this still begs the question, so why doesnt rain water that dissolves the muck on the window stain the glass?
ive got dirty windows at my home that the rain as rinsed the dirt to the bottom of the glass but it wipes off easy!

the water marks ive created on my custys windows WONT shift