Ok,
My pool is about 22,000 gallons as best I can estimate.

How much CYA would you guess is added to my pool for every 3 "" tablet?

So 3.3 ppm CYA per tablet per 10,000 gallons as an estimate. If I am roughly twice that then every puck would be ~1.7 ppm cya.

When I measured the 40 PPM cya I have added water a few times and backwashed and had some heaver rain so it diluted a little. I was planning on using a few trichlor pucks on while on vacation so I didnt have to depend on stepson to add bleach every night. I dont want to go over board with cya though.

Mike