hi
i also use the same brush , what system do you use, and what flow rate? , as this will determine to a certain extent what finish you get rinsing brush on . also how many times have the windows been cleaned , as i always rinse brush of on initial cleans - only rinsing brush on once i have windows up to scratch . having said that some windows -but not that many, need to rinsed brush of , you get a feel for it after a while. also brush angle plays a part , i set mine so dirty water runs to back of brissels , and not back on to window.
daz