1. Approximately 2.5ppm

2. Never add 11 lb. of anything at once. You may either overshoot your target or end up with cloudy water. Add a box of Borax and wait several hours. Then retest pH and redose if needed. Anywhere between 7.2-7.8 is ok. Once your pH starts to move, you might want to go to smaller doses than full boxes at a time. Do NOT test pH when your chlorine is high, however, or you will get a falsely high pH reading. Test pH before adding a new dose of bleach.

3. I don't know. I haven't bought any CYA lately.

4. When you can pass the overnight test, I'd keep the chlorine high for one additional day for added insurance and then let the cl drift down and maintain it between 3-6ppm all the time.