The trichlor pucks are acidic and are driving your pH down. Continue to work on bringing it up. Washing soda will raise pH and alk whereas Borax mainly affects pH. Adding it slowly through the skimmer while the pump is running is the correct way to do it.

What is your chlorine reading in the evenings when you test (but before you add bleach)? How much chlorine are you losing overnight?

Go ahead and test the CYA level and report it. You can always buy refills on the CYA testing reagent.