I too have an intellichlor system. The same is happening with mine also. It was installed in March and after the salt was put in, about 3 weeks later the add salt light was on. I added 40lbs and everything was fine for about 2 weeks then it came on again, added 40 more lbs, 2 weeks later same thing. I called the pool company that built the pool and brought a sample in and it showed 35000 of salt. They said it probably needs to be recalibrated. But so far they haven't come out to take care of it.