thanks for your reply,it was an omnitrolley i'm seriously concidering ,work is mainly domestic mixture of rural and estates have a backpack for now but need to rest back !!
not quite sure of " depends on how pure water is " isn't all pure water "pure" 
only use water that has reading of zero.. ?
do ever use use your trolley from your van instead of taking out ??
Darren
When I referred to water purity I did not know if you were intending to fill the trolley with water that had been through a DI unit or water that had only been through an RO. If the latter, you might want to consider having a trolley with a small DI unit - or at least having one fitted to it as an extra. Some designs of trolley may not have space to fit a DI unit AND a hosereel onto and could affect what choice you make.
For intance, I have a van mount which is currently carrying water at 005 TDS (this is how it's currently coming out of the RO). To fill the trolley from the van mount via the van DI is a slower process but at least I know it's 000 in the trolley. Other times I want to fill the trolley much more quickly straight from the van mount as I have the means to do this. However, this means that the water I use from the trolley won't pass through the van DI and will be 005 in the trolley. Therefore I have a small trolley DI too in order to make sure the water I use is pure. Some people will choose to filter the water to 000 in their static tanks thus negating the need for DI on the trolley.
It all depends on your setup and how you wish to work.
Sometimes I do use the trolley as a mini van mount but only if I have run the van mount out of water at the back end of the day or if something has gone wrong with the van mount and I don't have the bits I need to fix it on the fly.
