Put the new salt cell in - registered 3300 ppm salt and ran fine. Put old unit back in, registered 1600 ppm salt and shutdown due to low salt.
Took water sample to Leslies - they tested 3100 ppm and zero chlorine level, suggested my almost 5 yr old salt cell was likely dead.
Given it's sunny and the pool is still 79 degrees, I popped in the new unit and started a superchlorination cycle to try to avoid a green pool!
It's interesting - the original unit used to run 8-9 hrs/day at 85% and chlorine level was about 0.4. Lately, I'd run same length at 100% and level was 0.2. Also, first few years, it would lime up and need to be cleaned. Last 2 years, it never limed up - I guess it was cracking less and less NaCl to produce Chlorine. Guess it was slowly fading away?
Glad I pre-emptively ordered a replacement cell this summer - only paid $280 delivered.
Any recommendations beyond what I've done?
Every day is good, and some are even BETTER !!!!