Rob,
You are confusing many different problems...
1. The fact that the EasyTouch displays zero salt has no effect on how the cell is working.. It is just a reporting issue between the Cell and the EasyTouch.. As long at the cell's salt light is green, then that is all that matters..
2. The actual salt reading using the K-1766 is +/- 200 ppm, so it is the number to believe. The salt level the cell reports is +/- 500 ppm and is often outside this range.
3. No matter what the actual salt level is, the cell works off of what it "thinks" that salt is.. If the red salt light is on, then the cell thinks the salt is low and it will not work.
4. I always try to make the cell "happy" as long as I don't have to make the actual salt level go about 3500, or so. As an example.. If the actual salt level is 3000, but the cell thinks the salt level is 2600, then if I increase the actual salt level to 3400. then the cell will read that as about 3000.. This makes the cell happy and it will produce chlorine. If I can't make the cell happy without going too high on the actual salt, then most likely the thermistor in the flow switch is bad.. Replacing the flow switch will normally solve this issue.
5. Just because you have no chlorine in the pool does not make the cell bad. If the SWCG's "Cell" light is on, it is almost always making chlorine. Once you get algae a salt cell will never be able to make more chlorine than the algae can eat.
6. The first thing I would do is to use Liquid Chlorine and get my FC up above 5 ppm just before dark. Then do an Overnight Chlorine Loss Test or OCLT
Overnight Chlorine Loss Test
Thanks,
Jim R.