Since I was using calcium hypochlorite to do my shocking, and shocking ~1x/week, I am interested (and slightly concerned about) in my CH level (even though I know for vinyl pools the CH isn't critical). Although still waiting for my TF-100 kit in the mail, I took a sample to the pool store and they told me I'm at 450 ppm Ca2+ (not surprising). When I plug the pool store values into the CSI calculator in the Pool Calculator I get CSI = -0.57.
In the description it says "Less than -0.6 is suggestive of problems for plaster, tile, stone, and pebble pools. Greater than 0.6 is suggestive of problems for all pools." Does that actually mean LESS than -0.06 is suggestive of problems? So -0.8 is suggestive of problems for plaster/tile/stone/pebble? Or less negative, meaning the range from <-0.6 is the ideal zone, -0.6 to 0.6 is the risky zone and >0.6 is the danger zone?
I assume I want my CSI to be as low as possible? When I play around with the numbers it seems to be this way, but the wording in that description leads me to think otherwise.