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Copper clean-up idea

8748 Views 40 Replies 13 Participants Last post by  Buzz_Hog
I was gonna post this as a reply to the invert killer thread, but I though I would just start a new thread and get some ideas:

There has been a running theme of Cu contamination around here lately. Has anyone ever read about treating a tank with EDTA or some other metal-chelating agent to get rid of any trace Cu that might be adhering to the tank? You would want to do it while the tank is empty of anything living, as EDTA will also chelate Ca and Mg and other "good" metal ions, but the thing about EDTA is that once it has chelated to the metal ion, you can just wash the EDTA-Cu complex away. And since reefers usually add PLENTY of calcium to a tank, it wouldn't really matter if there was a little left over in the tank, it would disappear after a few water changes.

The EDTA might also "draw" the Cu out of the glass and silicone etc, as it would bind up free Cu and then the equilibrium would reestablish itself, releasing more Cu from the glass/silicone etc into the water. I could imagine soaking a tank in a solution of EDTA (for days, possible changing the EDTA solution a couple of times?) as a way to clean the tank before setting it up.

There are also other metal chelators out there, EDTA is just the most common. It is used for lead poisoning (you actually drink a solution of EDTA, and the EDTA-Pb complex is excreted).

Am I nuts?
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Let me dig a bit

I don't know if you can buy EDTA in a store - I can check around. If not, I can order you some through my university contacts. EDTA is pretty innocuous on its own as far as I know. I'll double check on that too. You would definitely want to try to get rid of most of it before you put anything else live in the tank, because it would scavenge Ca and Mg. The good news is, it is stoichiometric (my $1.00 word for the day), so as long as you didn't continue adding EDTA to the tank, you would be fine. Even if you didn't get rid of it all, it would only soak up a certain tiny amount of Ca and Mg, and then it would be saturated.

It will work in theory...:) And it might save you from having to toss some good equipment...
Cheap would depend on how much you need, and I don't know how to figure that. At the most, it is $46.00 for 100 g. Our lab probably gets a discount.

I've also put in a request with an environmentalist water person friend of mine to see how copper contamination would be cleaned up in the "real world".
cyberchef said:
The only way I've heard of for getting Copper out of a glass tank is with acid baths. Dangerous to say the least. I believe that Edta will only bind with metals that are in solution but since I'm not a chemist I can't say for sure.
It does only bind in solution. My thought was that the EDTA would complex any free copper, and then the bound copper (in the glass, etc) would leach out into solution to reestablish the "equilibrium", and get complexed, causing more copper to leach out...etc. I can write out some chemical equations for this, but I don't want to be responsible for any seizures that could occur among unsuspecting readers.


Which acid have you heard of using? Nitric would do it, but would probably cloud the glass in the process if you weren't careful.
Buzz_Hog said:
How about a sledge hammer and $99 to buy a new 55 gallon.... :)

Nothing better than relieving stress and curing the problem of a Copper Riddled tank....
Agreed. :beer:

I just got curious, being the geek that I am. It just seems a shame to toss good equipment when a bit of a soak might fix it. On the other hand, the sound of smashing glass is quite satisfying at the end of a particularly frustrating day...

Danielle - what is BAL??:confused:
Buzz_Hog said:
Or you can try cucumber rinds... ;)
That would actually be a pretty neat solution. It is possible that the proteins have to be extracted before they can strongly bind the Copper in solution, but it is also possible that they don't. Did any of the papers say if the copper-binding property was utilized biologically? If so, the binding site might already be occupied, and it wouldn't be so simple. But definitely worth a try.

I am really curious to know what is in the commercial product...there are lots of ligands that could form really strong bonds with a metal.
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