No idea how much resin i use as i used to use ro only and the Collins 450gpd was producing around 7-9 ppm from 300ppm from tap
Now i have a 25l di i got off Damo but it is full of nuclear grade resin which had been in it ages and still producing 0ppm so not had the opportunity to change it and then work it out by the next change
Suffice to say i am not on a meter and use anywhere from 200l to 400l per day and it costs me nowt
Got the ro second hand with almost new membranes so can't comment on that either but I've been using it about a year
Now i have a 25l di i got off Damo but it is full of nuclear grade resin which had been in it ages and still producing 0ppm so not had the opportunity to change it and then work it out by the next change
Suffice to say i am not on a meter and use anywhere from 200l to 400l per day and it costs me nowt
Got the ro second hand with almost new membranes so can't comment on that either but I've been using it about a year