Just an FYI if you have never used Cupramine before.
"Prime, like most water conditioners on the market, is a reducing agent. *Therefore, when combined with Cupramine, has the potential to reduce the copper from a safe form to a more toxic form. *We do not recommend using the two products in conjunction with one another. *However, since Prime only remains active for 24-48 hours, you can prepare your tap water 2 days prior to adding to the aquarium and it will be perfectly safe. *At that point, the Prime will have dechlorinated the water."
Two days after Prime is added the water it will still be dechlorinated and will not react with copper. *
Product Support Seachem
