I was one of these cleaners who couldn't get my head around what Peter Fogwill was saying with regard to increasing water flow reduces cleaning time.
He is right, but I have also found in my case that if I turn my controller up too high, I do use more water and don't achieve much more. The ideal for me would be a slower flow on the wash and scrub and a faster flow on the rinse.
I also put this down to my age and health, as I can't physically keep up with the speed needed to work on a full flow. So for me, what works in theory doesn't always work in practice as other things come into play, especially after I have been working for a couple of hours.
In the early days I started off with Peters tailer system. We had a Vikan brush with Unger Teleplus poles and 3mm jets. 1/2" garden hose was the supply medium. I carried and extra 100 litres in barrels in the van and would get through all my water by early afternoon (475 litres). As I was processing water directly into the trailer overnight, I couldn't go back for a refill. I could never get Peter's by pass valve to work for me TBH.
When Williamson's brought out the Varistream flow controller, turning down the flow rate reduced our water usage and I accomplished more
with less water, so you can see how Peter's advise didn't make sense to me.
My son loves our backpack as he finds hose management very frustrating and time consuming. But the time he saves pulling his hose out to start cleaning is lost with his slow rinsing time. I find the flow rate painful when using it occassionally.