Richard,
I run a adjusted TA of about 70 ppm (which means I run a TA of about 90), pH of 7.6, salt about 3400 ppm, Cal around 220-250 ppm, and temp around 82 when the heater is on. See what those give. BTW, I have seen no corrosive action to the water. Try plugging those numbers in and see what you get.
Evan