Buying big bucket of CYA or just as much as you need.

[JimK]

According to Chemgeek there are two things that will degrade CYA, certain bacteria and shock levels of chlorine. Bacteria can occur during winterizing and the shock levels are often present at opening.

If interested, you can read more about it here: Degradation of CYA

Interesting. I didn't know shock levels of CL also degraded CYA.

Always learning something here.