Adjusting Pentair Intellichlor IC40

[newpoolguy]

I live in NJ. This is the first season with our new pool. It's an inground pool that's 12'x30', approx. 8400 gals. I'm trying to adjust the Pentair Intelichlor 40 SWG. When the pool was opened for the season, it was shocked causing the chlorine to be off the charts. Per the users manual, I turn the unit of and waited for the Chlorine level to get to 2.0-4.0ppm. When it got to 3.3 I turned it back on and set the unit to 60%. after 24hrs. I measured again and Chlorine was 5.35 so I lowered the unit to 40%. After 48 hrs and no pool usage due to some cool weather, I measured it tonight and it's 8.1, so I lowered the unit to 20%. I'm going to wait another 24 hours and see if the Chlorine goes down. For the record, I'm running to pump from 10am to 6pm.

Am I doing these adjustments correctly? If I'm not please give me your advice. Should I change the length of time the pump is running? Should I run it at a different time of day?

Thanks for your help.