Yep. More chlorine. Use the chart at this link to get an estimate of how high your chlorine is:> http://pool9.net/oto-chart/
Then, add enough bleach to get the chlorine back up to 20ppm again. (Remember, in your pool, each of the 121-oz jugs of 8.25% bleach will add about 3ppm of chlorine.)

Continue running the pump 24/7.

By the way, your pH test will be invalid when the chlorine is over 5ppm. You'll have to dilute the water sample by mixing one part pool water with an equal part of distilled water. Then, run the pH test with that mixture. Do this before you add the next dose of chlorine.