i also use an aquatap on my system to keep water usage to a minimum.
As an example today i cleaned 23 houses, approximately £260 in earnings and used approximately 250 liters, started at 8.45 and finished at 3.00, with two 20 minute breaks, i run on 60 (psi) pure freedom digital controller .
I personally find the faster flow rate helps me work faster, maybe its psychological, am sure you could get the same results with a lower rate, i dont know, each to there own, but it works for me, also i am using hot water at the moment