Just to clarify
2x19ltr di vessels at both RO's
I realise the output tds of the merlin is 40% higher than that of the 4040 but look at the figures, the dowex has lasted approx 3x that of purolite.
The costs are minimal - and results have been calculated per litre of resin x 25 to calculate for a bag.
All I'm saying is that resins differ in quality vastly. Anyone wishing to experiment with their own water samples then feel free to do so, as the chemical composition of resins are different to one another one resin may work better up here while down in the south east a different resin may outperform dowex.
For us the costs are minimal, having to replace a bag of resin every 20k ltrs ain't a problem, never mind 10x that! especially as for most of us 2ltrs=£1 earned or thereabouts.
Dave Morris - honestly mate, twin di in each van would still be very simple, save lots and lots of resin and guarantee quality water. If you are interested in maximising profits then you have to consider lowering expenditure. A penny saved is a penny earned.
DA - do you drive a white berlingo? I was talking to a guy months ago in a white berlingo, think he was called doug or dougie or something, at the airport (I was waiting to pick up a friend). Was that you? Moustachio!!