I have been following the TFP methods since my pool was installed in 2007. I now have seven successful seasons behind me and have a good understanding of water balance and chemical requirements. I have been unhappy with the Jandy Aquapure SWG and PDA control system since the beginning and have replaced several circuit boards and flow sensors over the years but still have the original SWG cell. This season, I noticed that I have needed to increase the SWG percentage over prior seasons to achieve the same chlorine level at a given CYA level. I have no error messages and the SWG appears to be operating normally. I have also confirmed that the salt level displayed on the SWG is accurate by using a digital meter calibrated for salt.
So, if organics are ruled out by a OCLT, is it safe to assume that the cell is beginning to fail or is reaching its end of life? Is this normally how they fail?