Copper treatment questions

[berkdog]

If you have some problem and need to treat with copper in a QT... and assuming that you have all of the treatments and tools/tests necessary... how should (or would, or have ) you perform(ed) water changes?

a1) Remove 10-25% of water from the QT.
a2) Replace this with newly prepared water (with same salinity, pH, temperature). Add additional copper, while testing copper levels between each couple of drops.

b1) Remove 10-25% of water from the QT.
b2) Replace this with newly prepared water (with the same salinity, pH, temperature) that has also already been treated with the correct amounts of copper levels.

I would assume choice (b) to be the best because in (a) there's a high potential that copper levels drop in the middle of the testing period. What options are there?

Or if the QT is already completely cycled and ammonia, nitrite levels are continuously null, should you avoid water changes completely (if possible) during a 2-week copper treatment?

Thanks!

[leebca]

Either is okay, but there is a very slight advantage to b.

[berkdog]

Thanks. I wish there was a fish hospital. Before getting fish, you really have to become a fish doctor!!