Closing chemistry recommendation

[FormerBromineUser]

They also told me that when chlorine oxidizes Polyquat into smaller pieces, they are still fairly effective.

And the question is???

If you want the assurance of an algaecide on closing, and also want to close with shock level FC, this is your answer. "Fairly effective" sounds like a plan.

Doesn't seem like allowing FC to drift down before adding polyquat makes a big difference when you close at shock level because your FC will still attack the PQ.