With the OTO test it's really, really difficult to tell the difference between TC and FC especially when using dilution.
If your CYA is 80, your shock level is 31. Since you don't have an FAS-DPD test, you have to maintain shock level until your water is clear. If you had an FAS-DPD test, you can shock until the FC holds overnight and the CC is .5 or less. You simply can't confirm this with an OTO tester.
So you have to keep it up to shock level until it's clear. How did your CYA go from 45 (great level btw) to 80 (too high for an non swg pool....)?