Sandy, that's pretty interesting, as I am now up 30ppm CH after 11 lbs. of cal-hypo (27K gallon pool, Pebblesheen, same Starite filter as you).

Now my TA dropped by 10 ppm to 70, so I just added 4 lbs. baking soda tonight to bring it up a bit. I'm not sure how TA might effect CH... I guess that's why they say YMMV. Thanks for sharing.