The short answer is...'til your pool clears. Again, I'd do 20 just this first time. Thereafter, bring it back to 12-14 each evening. Some folks here have cleared in just a couple of days. Others have taken a week at least. I suspect it's because they didn't keep socking the Cl in there. If you can stand the cost, bring your Cl back up to that same shock level during the day. The Sun will consume most of it but it'll still do some good and speed the process. The primary thing to remember is to stay the course.....keep the bleach coming!!

It would probably be very helpful to plan on adding more bleach later at night when you put that first dose in. Maybe each night would be best.

Looking ahead, plan on changing your sand when your pool is clear. Sounds like you've got a plan and you're on your way.

Lot's of folks here have done this successfully....you'll be next. Get that kit so you can measure those high levels of Cl, that'll help you more than once.