Sorry to say but you have the wrong system, 195ppm is classified as hard water, therefor you should be using a RO type system to save on costs, your pure water must be 0 tds for intitial cleans, you can get away with up to say 9 ppm at the worst on repeat cleans, but it sound to me you are using the wrong technique.
First you must clean the frames from the top horizontly then the virticals side to side then the bottom of frame, then go bacl to top and start to clean the glass on an up and down movement then rinse for top moving side by side on a downward stroke.
Some window cleaners use chemicals some use basic tfr , this is not the answer in my opinion as if its not washed off properly it will leave streaks and could contaminate the brush if it were left to dry, especially in the hot sun ( when we get them), PURE WATER is good enough, but a good tip is to buy some Swift & Sure , its a disinfectant/sanitiser Glass treatment, great for the removal of algae from glass and cladding even for conservatories and green houses.this product can be used in a diluted state through a micro trolley system give the frame a good clean then the glass, removing all micro oganisms from the surface then rinse off with Pure water in the normal way, you should see the water beed off like never before.
if you dont have access to a trolley system then just dip your brush head into a solution in a window cleaning bucket and clean frame and glass, then rinse, brush with pure water and continue to clean in normal way, the results are second to none, if you are near the sea windows can get very dirty with sea salt and dust particles this is ideal for use in that type of environment aso great in heavy traffic areas form carbon deposits.
Another tip, if its long frequency cleans like every 6 to 12 months like schools etc its best to use it on all these types of cleans, if you working a 2 or 3 man team get one guy to wash frames and glass with the trolley and solution and the other guy/s to clean with pure water in that order, you won't be dissapointed.
Ive being at this game over 13 years and was a former BDM with Ionic Systems and an assessor/ instructor for the BWCA (North). for any help call Steve on 07771523669
I would advise you take a WFP training course with the like of the BWCA , its worth the money believe me.