Cupramine, Quarantine and Water Changes?

[Jon!]

Hi all. I am in quarantine with Cupramine with some new fish and all going great. I'll keep at therapeutic levels for 30 days and want to be ready to do water changes. Can I do a water change, replacing with new saltwater that's dosed with Cupramine at full therapeutic level (ie 1ml per 10.5 US Gallons)? Someone I spoke to had said that Cupramine actually takes a few days to reach thereapeutic levels in the tank - something about a slow release. And this does not refer to the recommended 48 hour step up as recommended when initially exposing fish to Cupramine. Is that an issue and will my copper levels fall below therapeutic levels?