I have a Mineral Springs system installed in 2005. We opened the pool about 3 weeks ago; when we first turned on the filter the 'inspect cell' light came on, we cleaned the cell with acid as per instructions, and afterward the power and generating sanitizer lights came on. The cell looked completely clean. Last Wednesday, the lights were still illuminated and our FC was about 2.5.
I noticed yesterday that the power and generating sanitizer lights were no longer lit. When I turn on the filter, the 'no flow' light blinks for a bit then goes out, and then none of the lights are lit. I tested the water yesterday evening and the FC was near zero. Salt has been ~3600 since opening the pool--no change. The water is crystal clear.
Can't afford a new cell right now, so if the cell is bad, we'll have to transition to liquid chlorine. Before doing so, though, I want to make sure that is the problem. Could there be anything else causing this?
A few other possibly relevant things:
Our CYA is probably nil; the lowest possible reading in my test kit is 30, and it is definitely lower than that.
Also, last year we were still having our water tested at a pool store. Each time they checked, they told us our FC was zero, but the water stayed clear all summer long.