Inherited a pond, trying to turn it into a pool!

[Yeggim]

Given that I'm still backwashing fairly regularly, and therefore replenishing water from time to time, would it make sense to leave the CYA until the filter runs for rather longer, instead of diluting it when I top the water up?

Sounds like a plan.

At 12.5% overnight loss in an unstabilized pool, can I start letting the level drift down yet?

Thanks as always...!

Sometimes the testing times will influence that overnight loss number. With low CYA, testing a little too late after sunrise or a little too early before sundown might account for that extra 1ppm. What's your CC numbers?