You didn’t mention if this was on commercial buildings or homes. Commercial buildings typically have a rubber seal all the way around the glass. These rubber seals trap soap and dirt which can run down the window after you’ve cleaned it.
First, you need to be sure the TDS coming out of your pole is zero. If you don’t have an inline TDS meter, you can pick up a hand held one here for $20.
Second, if you’ve got a good filter system, and your pole brush is in good shape, scrubbing windows with soap solution is unnecessary. The pure water and the brush are enough to clean the windows. Part of your spotting problem may be soap solution that is trapped in seals or corners or window frames, and this trapped solution runs down the window after you’ve rinsed. I STRONGLY reccommend skipping the soap solution step in your process.
Third, rinse, rinse, rinse. If you drop the soap solution step in your process, then the first time you clean a building or home with pure water only, scrub those frames aggressively and rinse about twice as long as you would on a maintenance clean.
Fourth, if this is occurring on homes, you may be getting spots from oxidation in vinyl frames. Vinyl window frames oxidize. This oxidation gets released when scrubbed with a wfp. You have to scrub & rinse, scrub & rinse, and scrub & rinse until the rinse water runs down the window clear. If it has a milky appearance, thats the vinyl oxidation, and you have to scrub & rinse the frames more until the rinse water runs down clear.
Fifth, if occurring on first time commercial cleans, follow this process (after dumping your soap solution step). On the top row of windows, go along and scrub & rinse the top frame, seal, and top 2 inches of the glass. Work your brush in a way that you get the bristles up under the seal. Scrub & rinse this top frame & top 2 inches really well. Keep doing this for each window, at least 10 windows at a time. Once you’ve done at least 10 windows (the more you do at a time the better), go back to the first window. Scrub & rinse all the glass, except for the top 2 inches that you’ve already cleaned…this is important…do NOT reclean or re-rinse the top 2 inches. Scrub & rinse the side seals well. If this window pane is directly on top of another (“curtain” of windows), then scrub the bottom frame of the pane, and the frame, and the top seal of the window below it as you did for the top row. Rinse each pane, avoiding the top 2 inches. Go back to the first window of the next row down, and continue. Keep using this method to work your way from the top of the building to the bottom.
The reason you’re doing several windows at a time in this process is you’re allowing time for the top window frame to drip dry…then you’re coming back and washing the rest of the glass & rinsing away any crud that has dripped out of the top frame. This only works if you allow enough dry time, and only if you don’t scrub or rinse this top area on your second pass…doing so would re-wet the top area and give any residual trapped soap or dirt the oppurtunity to run down the glass.
