Aqua Trol display says 1900, pool store test (I know) says 2300. Doesn't really matter. If the AT says 1900 it will not generate. The testing number is close as I can tell by the tase of the water. My question is how does the AT unit compute the salt level? Is there a sensor in the generator or flow switch that determines the salt level displayed? Will a cell that is going bad give an inaccurate reading? Might be looking at a new cell if this one won't clean up, it looks to be OK but I will clean it again. In the meantime the pool is starting to turn greenish, so let the bleaching begin until I can get an accurate reading on my salt level displayed.