Yes, you need to keep at it. And, once you do hold the chlorine reading overnight and have a CC reading no higher than 0.5ppm, then we usually advise one additional day of the high chlorine levels for added insurance.

Regarding pH -- keep adding the Borax. You have a large volume pool, so 2 boxes of Borax having been added isn't all that much.

I would wait on adding CYA for now. Wait until you have this issue finished. But, when it is time to add CYA, you have choices.

+ You can use the dichlor which would be a good idea in my opinion because it will chlorinate and add CYA at the same time. You'll need to monitor the CYA level periodically because it will add the CYA fast. Dichlor adds 9ppm of CYA for every 10ppm of chlorine. But what kind of dichlor do you have? Some pool chemical companies are adding unwanted stuff. Look at the ingredients and see what it says.

+ You can use the trichlor pucks but it will take much longer to have any CYA build up. It won't be as fast as with dichlor. Again, read the ingredients on your pucks. They, too, are often blended with unwanted stuff such as copper! You do NOT want copper in your pool!

+ Another choice is to just add stabilizer separately and just use bleach or liquid pool store chlorine as your chlorine source. (See what kind of price your pool store sells their liquid chlorine for and what percentage it is -- usually 10 or 12.5%. It may be a better price for you than bleach especially if they sell carboys of the stuff and that will also be fewer bleach bottles to deal with since you have a big pool.)