I would wait a few days more and retest your CYA, to see where your initial dose got you, and then decide on adding more or not. You don't want to overshoot it, because the only way to reduce it is drain and refill.

Add the bleach at least an hour or so before the kids get in, just to be on the safe side. Add it slowly into a return stream, or pour it around the perimeter of the pool as far away from the walls as possible, following it up with a good stir from your pole brush or a broom. The idea is to dispurse the bleach as quickly and efficiently as possible so that the kids don't swim into a "pocket" of it. With the pool circulating for an hour or so, it'll be fine for the kids to swim in it.

When you're not losing any chlorine overnight, then it's time to change the sand. You can test this by checking the chlorine at night right before bedtime, and then checking it again early the next morning before the sun hits the pool. If you have no chlorine loss overnight, and the water is clear, then you know the conversion process is over, and then you can change out the sand.

Janet

BTW, your post this time showed up exactly like/where it should have!!