OK, have an older (square cell) Aquapure rig. About 6 months ago the cell started looking pretty gnarly inside. Warped / broken grids, and was getting error codes @ the LCD inside the control unit.
I had replaced the sensor about 2 years ago, so it looked like the cell was due for a replacement. Costs were - yikes - so I got a cell off eBay that looked good. It's a newer cell, with larger fittings, so the old was cut off, and the new plumbed in place without incident. Power on, and no more error codes. Selt production to 75%, put salt in the pool so the board showed 3.2 ppm, and life was good, right?
Wrong. Couple of days later, the pool is looking a bit green. Grabbed the test kit and chlorine is at zero. Arg?
Can one of you fine professionals tell me next steps to troubleshoot / determine the problem?