Pool math app vs cya chart

[nickprette]

36k gallon concrete pool
Tf-100 kit
Cya closer to 30 then it is 40

Refreshing my memory on slam technique had a rough opening, am I following the tfp site and using 12 or 16 as slam, the chart has a Star next To 20cya as if that’s where I want to be when the app says 30-60cya is ideal and that I’m outside of my target range when I enter 12 as slam

 

[mknauss]

If your CYA is 20, raise it to 30 ppm and follow the chart which shows a SLAM level FC of 12 ppm for a CYA of 30.
App will always tell you that you are outside of your target range when you are. SLAM is by definition outside of your target range. Ignore the warning when you are doing the SLAM Process

 

[JohnT]

The * next to 20ppm in the Chlorine/CYA chart means that level is not recommended.