I have as I said 130-150, which is quite soft.
I was advised that if I just used resin, I would get through a lot of it, so it would work out cheaper in the long run to use RO, although expensive to start with.
Here's how the q+a went:
I asked:
"I am going to be buying a WFP system in the near future, but just wondered if you had any advice. My TDS reading is around 140ppm, so wondered if I could get away with just using resin? If so how often do you think I'd need to change it? And would it be more cost effective to run with small RO, perhaps a merlin?"
Reply was (From wintecs)
"With a TDS reading of 140ppm you could get away with just using resin. Current price for 25L bag is £69.00 + VAT (incl. free delivery) and will generate 5000 litres of pure water. This is the most simple option for filtering water. A Merlin will involve more cost to set up, but probably will work out cheaper in the long run. However this generates 60%-70% waste water and is a more complicated set up.
If you have any more queries, don't hesitate to ring or email.
Kind regards"
I think when they said 5000litres of pure water, they meant with my tds readings, so do the math accordingly.
On the other hand, I know a guy who with water readings of 300-400ppm, had a 4040 RO set up, but got so sick of all the waste water and that it took AGES to fill up the tank, now just uses resin. He spends about £90 a week on the stuff! Madness, but he leases a van and equipt from a company, and they supply the materials, so not a great loss on his part I suppose!! Apparently he gets through a lot of work, I don't know how much, but probably does 40 hours a week.