Copper in Salt Mixes

[Syntax]

Hey all,

I've been quarantining new arrivals for a couple years now using Copper Power, so I've gotten used to how much I need to dose for my mixing containers. I kept getting higher levels the other day so I ended up doing a lot of testing.

The Hanna Checker Copper High Range is used for all my testing scenarios.

I use Instant Ocean for QT as well as my display. The QT water tested .30 ppm before adding copper. I found this strange so I tested my display for the first time and that too is reading .30.

I then tested my auto water change water and it reads .30. With that, I figured it was my ro/di water or the salt. Tested my ro/di water and it read 0.00, so it has to be my salt. I thought maybe it was a mixing issue, but my 700g display hasn't had a water change in about 4 days.

I went out and bought some Red Sea Coral Pro and let that mix in a small sample container for about 24 hours. Tested that and it read .21ppm. I don't feel it is the testing as I can get 0.00 from just ro/di water and I also can get the expected copper levels if I dose water that doesn't have salt added yet.

I've also used different mixing pumps to make sure that isn't the problem.

Has anyone run into this before?

 

[GlassMunky]

I think I remember seeing someone else on the forum having a similar “issue” and it ended up being margin of error for the test kit and nothing was actually wrong.

 

[Randy Holmes-Farley Verified Community Expert]

There's no problematic copper in commercial salt mixes.

That checker is not suitable for measuring low levels of copper in seawater. many folks get such false readings, and when folks try, they can confirm they are false by ICP..