Quote Originally Posted by Oliver
How much copper is now in the water from the copper pipes in your aquaponics system? I do not know, but it will be more than if you didn't use the copper pipe to begin with.
Literal LOL!
Your logic is irrefutable, Oliver :=)

I do hope someone with the interest and resources will do this experiment.
The results would interest an awful lot of people, I think,
and potentially save many fish by supporting the "common knowledge"
or save a lot of money and head-scratching
by freeing us to use copper with confidence.

davidstcldfl's comment on pH (and bsfman's counterpoint)
suggest an important variable to be examined as well.

Foodchain, I am fortunate enough to take my water from a creek
which originates in a glacier just above my property.
When I was a youngster, a local murder was solved
when the remains were discovered in the municipal water tank.
By that time there wasn't much left but clothes and bones,
but the local bottled water industry did a booming business for a while...