2 hours to fill 1 25L BARREL?
it take me about 50 mins to fill 10 barrels DI only.
your tds is quite high for just DI only BUT it will be a lot less hassle bumper.
just follow instuctions you got with the trolley regarding calibration.
by the way i also have a 50L FREEDOM TROLLEY.great bit if kit.i have flo rate on 60 most of the time.
get 30m of streamline 5 extension hose(available from pure freedom).saves you moving the trolley as much.
best wishes
dazmond