Opened my pool about 7 weeks ago. Salt level was very low( off scale) added 2 bags from Walmart. Level came up to 2500 ppm. Have added 2 more bags since and still says 2500? Wondering if my cell is bad? The "inspect cell " light keeps coming on. I hold the button down to reset it but still comes on after a day or two. I would think there should be enough salt by now. I have had the generator for 4 years now and still the original cell. Time to change cell?