Time frame for copper

[Wildreefs]

I’ve been running copper in my display for last 70 days. Test levels twice a week, very little absorption , may drop from 2.0 to 1.96 in a week. (Copper power checked by Hannah checker)

I’ve added two fish yesterday to the tank, which hopefully are the last i add. Copper will have been running 76 days so any ich prior to treatment should have hatched and met copper by next week.

My question is , how much longer should I run it to shield the two new fish from dropping off ich/velvet from getting tote substrate?

Meaning they went in yesterday, they shouldn’t get infected from the tank, by how long can they let off the parasites?

I’m thinking 3 weeks from now then start removing it.

Thanks

 

[HotRocks]

30 days from the point the new fish were added.