Since you have granular CYA, it's straight to "BBB". 2.5-3 pounds stabilizer will bring your pool to 50-60 ppm CYA which should be good. CYA dissolves very slowly, we usually recommend putting it in an old sock and hanging that in front of the return squeeze the sock a few times a day to help it dissolve. Don't bother testing CYA until a couple days after the sock is empty.

Test and adjust chlorine frequently until you know you're staying above the minimum all the time.

The pH test in the K-2006 is easier to read and it has FAS-DPD for chlorine. You could add a Taylor K-1515 FAS-DPD to your HTH 6-way to achieve a similar set of tests.