CYA during a SLAM

[Baseballmom9]

I've started the SLAM process. My question is do I need to check my CYA levels DURING the SLAM and adjust chlorine accordingly or just stay concerned about keeping pool at shock level? I already checked it before starting the SLAM along with my other levels and adjusted where needed.
Thanks!

 

[PAGirl]

You do not need to recheck the CYA unless you have a large loss of water and a refill. Basically, you just check FC and CC during a SLAM, as the PH is inaccurate when the FC is over 10. After you pass all three criteria for ending your SLAM you can recheck everything after the FC comes down.

 

[Mr Bruce]

Unless you have big water exchanges (lots of vacuuming to waste, for instance) your CYA will stay the same so no need to test often.

 

[Baseballmom9]

Great! Thank you! Another question, when I vacuum, should I be vacuuming on the waste cycle to avoid the water exchange? Will the dead algae hurt my filter?

 

[PAGirl]

It should not hurt it, but it may make you need to backwash sooner. You should backwash when your psi rises 25% over the "clean" pressure.