To Shock or Not to Shock?

[cschnurr]

At pool opening in early May, I topped up CYA to 70ppm per Aquarite SWG recommendation (60-80ppm).
Last Thursday (Day 1), I measured CYA = 55ppm, so I topped it up a 900g bottle CYA which should have put me up around 65ppm.

On Saturday my readings were FC=3ppm CC=0.
Anticipating a family party on Sunday, I increased the SWG output. On Sunday before the party, I had FC of 5ppm (didn’t measure CC).
Since Sunday, I’ve noticed the water has a green tinge, does not sparkle, and there is a small trace of what could be algae on the bottom of the pool.

Tuesday, (Day 6) I measured CYA and it was 80ppm.
It’s a subjective test so I’m thinking the delta between my expected 65 and the measured 80 is the result of measurement error of each result.

I vacuumed the pool (I didn't backwash filter yet) and now have the pump running 24/7, no sign of any CC, and when I turned off the SWG overnight, the FC is maintained at 5ppm. The water has visually improved slightly, but I still have a small trace of what could be algae on the bottom.

My current readings are
FC=5
TC=5
CC=0
TA=100-110
CH=250
CYA=80

My theory is that the CYA I added ‘tied up’ existing chlorine just as I increased the load on Sunday which may given algae an opportunity.

I will vacuum again and backwash the filter.
What do you think, should I shock, or let the the pool clear itself?