Closing....when to add algaecide?

[JimK]

What I do is bring my FC up to shock level, then I put in a quart of 60% Polyquat algaecide. I wait 48 hours for the FC to drop, then test the water, and add chlorine to bring it back up to shock level. Then I close. This generally keeps me from having a problem in the spring, if I open early enough.

Thanks for sharing your experience.

Supposedly, according to what I read, high chlorine levels break down the algaecide, hence my question. I guess what I'll do is shock then wait until chlorine drops back down to a "normal" level (about 5ppm in my case with CYA at about 80) before adding the winter algaecide.