Well at 10% and 20,000 gallons that only brought you 75ppm cl.
Does your kit test for Total Chlorine or Combined Chlorine? That value might be helpful to know.
Your pool consumed alot of chlorine in a sort period of time.
If the bleach burned out all the remaining goo, and the resultant Combined Chlorine, and then was baked off by the sun, great! but, you won't know your done until you're sure your CC is less the 0.5 ppm and you don't lose more than 1 ppm FC overnight at shock level and maintain shock level for one more day.
It is important to get to FC to shock level and keep it there for a while.
You can't know your shock level without a CYA test.

Sounds like it's getting alot better - you'll get there.