I have an Ecomatic ESC 36 for my AG 25k pool that was having trouble keeping up at the end of last summer (the 4th year in use). I'm debating replacing the cell with a non factory original (Compupool) for $350 or an OE for $700 or just scraping the system for a new IC or Autopilot system. I've been happy withe Ecomatic's performance but fear replacing the cell only to find that isn't the problem or isn't the only problem. Is 4 years about what I should expect to get from a cell? What are your recommendations for a new system?