As long as you stay with 1 cup or less at a time of bleach, you won't be adding too much...but without stabilizer in the water, whatever you add will be gone in less than an hour's time, which is why you put in a reasonable dose (1/2 cup) but it wasn't there when you re-tested.You're right that the sun will degrade whatever bleach you put in, so you actually could put in 1-2 cups at a time (2 cups would take your FC to 12 ppm temporarily), and the sun would burn it down pretty quickly. I would probably put in 1 cup, stir it around, let them swim, then follow that with another cup after they got out.

Keeping the trichlor pucks in the pool will help--just don't let the kids play with it and I would remove it from the pool while they're swimming. It can take a few days for the pucks to dissolve--they don't normally dissolve in just one day's time.

Janet

Janet