If you add 2 scoops of powder and it does not turn pink, then you have no chlorine.

Yes to adding more bleach and keep an eye on the pH. You are ok at 7.2 but don't want it lower.

Can you dilute a water sample (1 part pool water, 1 part distilled water) and then run the CYA test with that mixture and multiply the result by 2. Then, post with that result.