On first cleans I use a high flow , go over frames giving top frame a good scrub , then quickly over glass, rinse top frame , go to next window, do this on whole of the house, then go back to first window, and re do, this time glass only , should come up good , unless you've got problems , like the ones stated by mikecam, as for the water flow from pencil jets 8 inch is not enough , try 2 - 3 ft , I use this all the time , and get very good results, one last thing , I always rinse brush of on new cleans , IMO fans would make the problem worse.
Daz