I haven't added salt to my pool in a couple of years. My Jandy unit has always shown between 3.0-3.5, and occasionally I take the water to a local Leslie's for a second opinion, and he's always said it's fine.
About a month ago, I started getting error codes on the Jandy that indicated I needed to clean the flow sensor (which, if I understand correctly, is the part that reports back to the hardware about the salt concentration). I cleaned it with a lightly abrasive sponge, just as instructed. I didn't see ANY visible change as I cleaned it. (There was no coating, debris, or anything else -- the contacts looked bright and shiny before, and are bright and shiny afterwards.)
When I reassembled it and turned it back on, the Jandy now showed 1.7, which is dangerously low. I double-checked this with some salt cell test strips (Aquapure) which confirmed about 1.5. So I bought a few bags of salt, dumped them in, followed instructions (turned salt cell off for 24 hours, mixed the water well, etc.). The Jandy barely budged -- about 1.8. According to my calculations I have about a 15k gal pool. But who knows. Maybe I mis-measured it and it's 20k. (Hard to tell because it's odd-shaped.)
Long story short...after 5-6 strips to the store over 2 weeks to get 2-3 bags of salt each time, I finally got the Jandy to report 3.0. I double-checked this with Aquapure check strips which showed me about 2.9. I figured OK, at least we're back in "acceptable" territory, so I turned the salt cell back on, and the Jandy appears to be working and isn't reporting any errors.
However, two days later, I checked the Jandy, which now shows 4.1 salt concentration -- YIKES. I used the test strips which still show 3.0. I turn it off and on again; it shows 3.0. Then it climbs to 4.0.
Basically...I'm wondering if this (older) Jandy unit could be malfunctioning (even though there are no error codes). Do I trust the Jandy? Or do I trust the test strips? Or what?? It seems like every time I test I'm getting different answers, and now I don't know what to do.
The water tastes noticeably salty, if that means anything.