Update: Pool guy wasn't willing to try to remove pool light. Hope no lurking algae back there but time will tell. I removed the treads on ladder the other day while still shocking.

I'm now letting FC drift down. Water looks great, very clear. FC = 7.5 this morning. On Thursday, CYA wasn't showing up when tested (not sure what happened) so I added 3 lbs. through a sock. That being 1/2 the amount needed to get CYA to 70. I am leaving town in the morning for 2 weeks. So, I won't get an accurate read on CYA until next Thursday???? What do you suggest about adding more CYA? I'm checking FC and pH daily.
Thanks.