I found this in a hot tub forum: One interesting thing is when the tech came out to replace the first cell he said Watkins had changed the salt requirements down to 1100 ppm.  Both the dealer and the customer support person thought that may have been the reason for the second cell dying.  Customer support said it is in fact the other way and now they want 1750 ppm and that the lower salt level may have killed the second cell because it was working harder than needed. In reading a 2010 version of the Ace manual, It has a target range of 1000. A Hot Springs dealer I know likes to target 1750. I have been dealing with salt since the late 1990’s when salt systems required 5000, then 3000 and now 1500-2000. Going below 1500 will cause the system to be on much more because there is a lot less salt to convert. Salt cells are rated in hours so the more they have to be on, the shorter the lifespan. To get a longer life from your cell do not go below 1500. I would recommend keeping it as high as the Ace system will let you around 2000 which will also make the water a little more silky. This will allow you to reduce your level which will allow your Ace cell to last longer.