No, the shock level is determined BY the CYA level. Pool size determines how much chlorine you'll need to actually get to that level.
One question though - I'm gathering, despite the size of a pool, it can be taken to ANY shock level, no matter what the CYA is. Is this right?
If so, what's the harm in ramping this thing up to 19 next week? I mean, would the plaster or paint or ladder fall off the walls? Why not go "all out"?
It is hard when someone working for you will not listen. You sure did try and spent a LOT of money. HUGS to you for trying so hard.
I like your idea of having the tenant taking care of the pool. They get to enjoy it so they should take care of it. TFP is really based on day to day care. The money to pay someone from outside the home to care for it is not good as you found out-OUCH!
Kim