hi
no need for a seperate sprayer,
what i do is spray tfr, viro sol , or what ever you use directly on to brush head , extend pole , turn water on , and soak gutter , fascia, without touching with brush,
turn water off (easy if using an aqua adapter) then scrub with brush , the neat tfr on brush foams up ,
leave a few mins , then turn flow on and wash as normal, works a treat, much quicker, uses less tfr, and fascia comes up a treat.
daz