Question:
I need a water softener and RO unit for my house (24 gpg, TDS 450-500, plus tannins) and have been quoted the following installed including an extra 2.6 gal storage tank for my RO (I have a fish tank I wish to use it for):

32000 gpg softener (Fleck 5600) + tannin removing resin: 1100.00 PuRO 50gpd RO unit: 485.00 + 55.00 (for extra 2.6 gal tank)

A friend of mine said you can not use sodium chloride softened water to feed an RO unit because it shortens the membrane life and instead should use potassium chloride, I have never heard of this is this correct?

Answer: Having done a lot of r/o work for many years, and being certified in r/o by the water quality association, I'm surprised to see the advice about sodium chloride softened water shortening r/o membrane life. I've never heard that before and would like to see the source of the information, if you could ask your friend.

The r/o manufacturers will typically recommend changing a residential-type r/o membrane at 3-5 year intervals. I have seen many go twice that - and on sodium chloride softened water. I mean no offense to your friend, but my experience does not support your friend's advice.

What will keep a membrane going a long time? Soft water and regular filter changes.

I have nothing whatsoever against potassium chloride, but you will spend more using it.