There is nothing wrong with a CSI of -0.37.
For PH, TA, CH, I focus on CSI and I regularly keep it within -0.6 and -0.3. My pool's plaster is going on 20 years old and still in fairly good condition without much etching at all. Etching really doesn't accelerate until well below -0.6.
Using the Calcium Saturation Index (also known as the LSI in the pool industry) as a guide for maintaining proper pool water balance and to protect pool plaster, including quartz and pebble finishes, has become a mainstay in our industry for good reason. Several experiments have been conducted...
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Only because it is really hard to measure a PH above 8.0 and because it can be an irritant to the eyes.
You are being too restrictive about the levels. Again, there is nothing wrong with those ranges.
Don't confuse recommended ranges with absolute limits. There is a lot of margin built into the recommended ranges and operating outside of the recommended ranges is not uncommon and sometimes necessary depending on unique conditions.
Increasing CH would be the last thing that I would do as it is difficult to reverse. Focus on TA & PH.
However, I have operated my pool at CH levels close to 1000 ppm in the past because of very high CH fill water and drought restrictions.