Update - Around 9pm last night I added bleach to FC Shock level based on pool math. This morning (day 5) around 7:30am we were back down to 13.5 FC. Pool still looks the same as the pics posted yesterday. Added more bleach based on pool math; continuing to brush and vacuum. During this process, I've backwashed twice when the gauge showed an increase from normal; will do it again today for good measure even though the gauge doesn't indicate a need.