So we've been at this house and I've TFP'd this pool for a bit over a year. I have not replaced an exceptional amount of water - just what's used by backwashing the filter when needed.
Every now and then I'd get a hint of a salty taste from the water. My curiosity got the best of me so I bought the Taylor test and did my first test last night. Ended up with 2200 or 2400 depending on drop I decided made the 'salmon' or 'brick' color. I've never added salt to the pool other than what is added by bleach or liquid chlorine. So I was somewhat surprised it was that high. I like the feel of the water so I'm not complaining.
My FC demand is 3 to 3.5 in the heat of the summer so I can see the salt adding up fairly quickly. Plus the fill water is softened and that adds even more salt. But the CH stays nice and low...so I'll take that.
I don't see this as a long term problem as I'm eyeing a SWCG anyway. At least I won't need to buy as much salt then.
Just thought I'd share.