Difference between pool school and pool math app

Brazillianguy

Gold Supporter
Sep 5, 2021
30
Miami. FL
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
Hi Everyone,

Is there a difference in the recommended CYA/FC level listed on the pool School vs the Pool Math app? Cause I'm at CYA 60 with a SWG and it stays 4 recommended in pool school and in the app it's recommending 5-9.
Thanks