when you where all sat at home in the winter when your van mount where frooze,me went out with backpack and a limted amount of water 175 ltrs,so wfp the tops and trad the bottoms.
i still worked most of the time,
yes i wear the pack on my back and i do have a back problem,but find it worst when i have to carry it and leaning over to one side,
i also do a few houses that i have to walk though to clean back,old cottages,that make it worth my while when you see the backs,
i use the shurflo p/k and never had a problem,use on speed 2.
i see it as another tool that i have in the van todo that type of job,