Gaz iv run out of texts mate. :
Water will be out for you tomorrow.
As for your last question,how long is a piece of string
There are a few things that will dictate how long your resin will last,quality of the RO system,water pressure,temperature,quality of resin etc.
As a guide though when I had the old 300gpd RO system I put a 10 inch dI on it,I used the system for about a year and never had to change the resin
I used at that time an average of 250 ltrs per day.
Hope this helps,now get ya friggin hand in ya pocket youre giving us Yorkshire lads a bad name.