What is the best Calcite Saturation Index (CSI) for a saltwater pool

[waterbear]

I am going to gently remind you that it is a pool and not a science experiment. What is important in a salt pool is watching your pH and not letting it climb above 7.8. High pH is was causes scaling, period! Watch the ph and don't lose sleep over the CSI!

[chem geek]

You also need to be fairly far away from "zero" before problems are seen. As waterbear says, pH is most important to watch as it directly impacts CSI where a 0.1 change in pH is a 0.1 change in the CSI -- the other parameters have a logarithmic relationship so have to move pretty far and that generally doesn't happen very quickly as it can with pH.