Peggie, In August 2003 we installed a Lectra/SAN, new Raritan PH-II head, and salt feed in our 1987 Hunter 40. From August 2003 through October 2005 we used the boat intermittently on the Chesapeake Bay. I'd guess that was 100 days over the two years. In late October 2005 we started a trip down the ICW using the boat every day. When we noticed the yellow "extended cycle" indicator blinking even when we were sure we had sufficient salt, we flushed the system with muratic acid per the instructions. That was in late November 2005. Things worked well for a few weeks. For the past month we have been in the Bahamas where the water's plenty salty. Even here we've been getting a slow flashing yellow for the past few weeks. Today the system switched to a red light after about ten seconds in treatment mode. Should we retreat with muratic acid? It's been about six weeks of daily use by two people since we did the last muratic acid flush. I understand if we can't get it to "clean up" with muratic acid the next step is replacing the electrode pack. Is Raritan the best source for the electrode pack or can we get one through a discount retailer? And a final question. In open water when we urinate we have been short cycling the treatment. Would that practice lead to a premature need to clean with muratic acid or replace the electrodes? Regret this got so long, but I wanted to give you all the background I could so you knew what maintenance to recommend.