But then again, you can just test and ensure your water chemistry is balanced, according to the Saturation Index. This, along with the Self Cleaning feature of your salt system, should prevent calcium scale. As waterbear said, these chemical additives are more of a preventative product and can be quite an expensive option.

I love the guys at LaMotte and they have some excellent products. The quick read strips should (IMO) ONLY be used with a water sample under shade or indoor. So you can take a water sample then dip your strip once you're under shade, or dip the strip in the water, then go to a shaded location. If you do this in sunlight, my experience is that you have too short a window of opportunity to make your comparison. They are accurate enough, if you do it out of sunlight.