Hi Matt, the cheapest i've seen is
http://www.gapswater.co.uk/acatalog/Reverse_osmosis_kits.html for the 4040 kit.
I would use 300-350L 3 times a week, there isnt much in the way of maintenance with the ro, I would flush out the ro for a few mins after each fill just to keep the membrane's clear. The filters need changing at least every 6 months, even if you dont use that much water the Chlorine removing capacity goes after 6 months of use and Chlorine will destroy your membranes very very quickly. I got a little digital water meter to let me know when I've reached the reccomended capacity in Liters of the filters.
I dont have a di resin filter on my Ro, I have a larger di vessel on my trailer after my pump, with the di vessel, wherever it is, you just need to check the output tds once a week to make sure it's at 000tds.
I'm not on water charges so I cant really tell you if they are cheap to run from that perspective, but as regards filters ect, the filter set costs about 23, say you need to change them max 3 times a year thats only just over 70 per year.
With my 200gpd ro I have 148tds going in and 001-002 coming out, so my resin should last over a year, Whoo hooo !!
No need to apologise mate, we all have to learn somehow, and asking questions is the best way
A hint that I've found to be helpful, before filling your tank up, run your ro for about 1-2 mins, the tds readings when you 1st start it up are quite high, but after a couple of mins it'll be down to below 010.
Hope this helps, feel free to ask anything else, I might not know it but there's plenty of more qualified folk on here who will answer it
Tim
