As a soon to be new SWG user I am trying to understand and balance my water before I start my SWG. After I plug the recommended values from the "Water Balance for SWGs" into the Pool Calculator I find a Calcite Saturation Index of -.58 to -.2. The advice is to reduce the pH to 7.5 when the pH reaches 7.8. This one change brings the Calcite Saturation Index to -.44.
While I realize that with a SWG the pool owner must avoid scaling on the SWG plates the recommended ranges appear to be borderline corrosive to plaster. Also, the Calcite Saturation Index appears to indicate more corrosion than the Langelier Saturation index does. Which index is the better predictor of corrosion and scaling?