The salt cell in my pool looks like it could be on its last legs - the last few weeks testing chlorine using my basic DPD test kit it has been around 1/1.50ppm (chlorinator running 6 hours a day), I'm getting a TF-100 kit sent here to Aus soon so will be able to accurately measure it.
I was reading some comments that the cell should fizz/have a reaction as the water is going through it and also the colour of the water should be different than just clear. With my cell, there definitely doesn't seem to be any sort of fizzing reaction (fizzing could be the wrong word) and the water appears clear. However, calcium definitely builds up on the plates quite a lot - so is that a sign of how well it's working?
Last season it was consistently maintaining about 8ppm according to weekly pool shop tests (I know!) but that was very consistent. So strange it would drop down so much if that is accurate. The pool is nice and blue though, my CYA according to the pool tests is about 40 (will know for sure as soon as the TF-100 arrives... can't wait).