Hate being the devil's advocate here, but how did Leslie's come up with 150 ppm CYA. Was it test strips, because most CYA tests only go to 100 ppm CYA that I know of?

Just trying to save you draining water.

If you have to drain, you are looking at close to 10,000 gallons. That could fill up WaterBear's pool with some left over.

Seriously, draining is expensive, and so is filling it back up. I just had to refill our pool with 20,000 gallons came out to $70.

If you can find another way I would do so.

Pat