We have a new pool and I am just getting started sorting things out. The water chemistry is looking good (got the TF-100) but my ECO-matic system is still having trouble even though the salt level is set to the manufacturer's recommended level. It starts out with both lights green but after a few hours light #2 turns red. I believe the cell may be up to eight years old. That's when the house was built. Are there any other reasons the light would be turning red? I just finished shocking the pool about a week ago so the FC level is still high (around 8.0 ppm), so I don't know if the salt system is actually producing chlorine or not. I haven't tried cleaning the cell with diluted acid, but based on a visual inspection it looks pretty clean. Should I just keep going until the FC level drops to around 3.0 ppm and see if the ECO-matic keeps the level up? How will I know if it needs replacing otherwise? Lastly, I've read that the ECO-matic can be more finicky than other systems. Is there any truth to that? Thanks in advance for the help.