There is no doubt keeping a slightly negative CSI will help with your scale problems. In my case I am convinced I had a faulty cell. I kept my water and CSI absolutely perfect, and kept getting scale until the cell was changed. although I did add boric acid, the scale virtually stopped when Hayward replaced my cell. As others have said, if your CSI is where it needs to be, it is impossible for scale to precipitate out in normal circumstances. There of been times when my pH has drifted up to around eight, I still see zero scale since the cell replacement even when my water gets out of whack for a very short period of time. 99% of the time my water is balanced perfectly, good luck with figuring out your situation.
By the way, I see we live in the same metro.
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