With a CYA of 50, you need to be shocking your pool up to 15ppm and try and hold it there as best you can. (Chlorine levels are based on CYA levels. Take a look at the Best Guess Table" in my signature below.) Test as many times a day as you can and each time add enough bleach to get the cl back up to 15. There is no such thing as testing and adding bleach too often when you are trying to clear a pool. In a 22K pool, each gallon (4 quarts) of bleach will add 2.7ppm of cl to your pool. Use that as a reference to help you determine how much bleach to add each time you test. When you get to the point where you can go from sundown one day to within 2 hours of sunrise the next day without losing more than 1ppm of cl, I'd suggest holding the cl at the shock level one more day and then you can let it drift down and keep it between 3-6 ALL the time. If you let it drop lower than 3, you'll risk another algae bloom. The key to killing algae is to sustain the high cl reading, so tomorrow test and dose every hour or two if you can. You can either pour the bleach slowly into your skimmer or slowly in front of a return jet. Both ways are fine.

Your pH is fine. Don't add any Borax at this point. Borax is used to raise pH. Baking soda is used to raise alk. It will take 3 lbs.of baking soda to raise the alk 10ppm. You can add it slowly through the skimmer while the pump is running. After several hours, retest and you can add more as needed to get to 80-120. Having said that, let chlorine be your main priority tomorrow.

Run the pump 24/7 and backwash any time your filter pressure increases 5-10 psi over clean filter pressure.

By the way -- it is ok to add bleach and Borax or bleach and baking soda one right after the other.

I would not use any more trichlor pucks or dichlor shock in this pool this year. Your CYA is already at 50 which is great, but you don't want it any higher.

Try and get the good kit I told you about in the post above. It will allow you to test higher chlorine levels and you won't have to depend on the pool store for your testing. In the meantime, you can use a dilution method to force your kit to go higher. You'll need to do this tomorrow to measure up to 15ppm of chlorine. More info at this link:

http://www.poolsolutions.com/gd/how-...d-testkit.html

Keep us posted how things are going tomorrow!