Today's numbers, 8 days after I opened to green slime.

19,000 gallons, Vinyl, AG, 40'x16' rectangular FantaSea, 200# sand filter, 2spd Hayward SuperPump, 1hp
FC: 4.5
CC: 0
TC: 4.5
pH: 7.4
T/A: 40
CYA: 20
CH: ?
Temp: Cold

My water is crystal clear now.
I used
8 gallons of LC (12.5%),
4lbs of Di-chlor powder (left over from last season)
1 Tri-chlor tab, and (left over)
filled a floater with 1" Tri-chlor tabs twice (left over)
1 box of Borax

Since I still have tri-chlor, which I'm going to use until CYA=30, my plan is:
Watch pH. When it hits 7.0-7.1 (from the Tri-Chlor), I will add a box of Arm&Hammer Washing soda. This will raise my pH and my T/A, which is nominally low.

I put a skimmer sock in today, so I don't have to backwash as much.

From my POV, I consider my pool water essentially perfect. I won't actively make adjustments, but I will passively do so.

Now all I need are a bunch of realistic looking rubber snakes to try to keep the birds from cr@pping in the pool, which they've done more in the last week then they have done in the last 5 years.

Carl