This is from the tfp Wiki page on your swg. If the light is just flashing it means it is just a reminder to check the cell and doesn't necessarily indicate a problem. Double check this info with your manual.
INSPECT CELL Light
Aqua Rite salt chlorinator has a built in reminder to inspect and clean the cell every 500 hrs.
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If the Inspect Cell Light is the only LED light flashing, then you can reset it by simply holding down the diagnostic button for 3 seconds, then release. The Inspect Cell indicator will now reset and will later come back on after another 500 hours of use.