CH is calcium hardness, and has nothing to do with your chlorine or SWCG settings. Being able to smell the chlorine can be a sign of problems. Can you test for Combined Chlorine? Not common with a SWCG, but often chlorine smell is an indication that you don't have enough chlorine and need to shock the pool. What is your chlorine level?

I don't understand why your spa has different readings from your pool. Are they completely separate plumbing systems?

CYA level should be at whatever the SWCG manufacturer recommends. Some are higher than others.