Hello spappas,
I have a Goldline Aqua-Rite T-Cell 5 system and have had the same problem for the past year. I would get the same light indications and the unit would show a salt level lower than the listed range for the unit. I would take a water samples to the store and each time their test would show the salt level within the correct range. I called the manufacturer and was told a + or - reading of 500 ppm was "normal." This I thought was a problem. It was my understanding the unit had to have a minimum reading to 2700 ppm for it to generate chlorine. So for the past year I have been adding salt just to keep the level above 2700 ppm as indicated by the unit. Whenever I had a water sample tested by the store it showed a salt level 100-200 ppm over the maximum level. I believed the cell was reaching it retirement age (approximate 5 years of use) and I was worried what damage, if any, a consistent actually high salt level could be happening.
Well this past weekend it finally happened, total failure of the unit. I added salt as I have done before but this time the indicator lights always came back on. I once again attended "Pool School" on this forum and saw 2 possible causes. It was either the cell or the computer "motherboard." So I disconnected my cell and brought it to the store to be tested. Their test showed the cell was dead. They also informed me that there was a possibility the computer board was bad. This is when their "sale mode" went into action. I had a dead cell, a possible problem with computer board and the T-Cell 5 system was no longer being sold as a complete unit. I was thinking on buying either a T-Cell 9 or the T-Cell 15 system but decided to take a chance with just a new T-Cell 5 unit.
The cell arrived just about an hour ago. I installed it, and after a little problem with the configuration process, the cell is up and running on "Super Chlorinate" and appears to be working. I would not consider myself a pool tech but with the help of this forum, especially the "Pool School" I hope my problem was remedied. This appears to be a problem that will get progressively worse over time so I would call your pool store and ask if they can test your cell. I would not just keep adding salt because of the possible damage high salt levels can cause. Good luck.