My pool is about 2 years old. I don't believe the SWG cell was ever calibrated as my local pool store consistently showed lower salt levels than was reported by my equipment.
The equipment typically showed 3700ppm. The pool store (using test strips) showed 3200ppm and always recommend I add salt (which I have not been doing).
In the past few weeks; I noticed the SWG report 4200ppm. It's displaying this as a fault as the optimal levels are 3000 - 3500 for this equipment.
So I had it tested again at the pool store - still 3200ppm. I bought a Taylor K-1766 which does show 4200ppm. I've cleaned the cell several times according to the manufacturer instructions (1:10 muriatic/water for 5 mins).
The cell has since reverted back to 3700ppm and does produce Cl effectively. It does continue to fluctuate from time to time (maybe more often than that as I'm not watching it for 9 hours a day).
I'm guessing I need to
1) Clean the sensor
2) Calibrate to what the K1766 test is showing
3) Drain and refill
Of course the pool store remains adamant that I should add salt at this time . He also suggested that the fluctuating readings from the cell suggest it's near its' end of life.
Tests a few hours ago show:
pH = 7.4
FC = 4.0
CC = 0
TA = 70
CH = 450-500 (I can't get a clean reading on this despite several tries. Using TF-100, the solution turns violet/purple rather than blue)
CYA = 45
Water temp ~ 80. Air has been up around 100F the past week or so.
Any advice appreciated. Is the cell on it's last legs or do I simply need to adjust my chemistry according to what science (K-1766) is telling me.