<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by J.Warrick:
<strong>Thank you for answering my earlier post about pH and Copper.
I should have told you why I was asking. I was not concerned with copper comming out of solution in a reef tank, but in a holding system. I use copper sulfate to treat parasites in a quarantine system. I have been told by many people that they believe that their fish died because the copper came out of solution in their marine tanks.
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As I said before, the problem is that we don't really know the chemical state of the material holding the copper. There are a number of minerals that can occur in detritial deposits, any one of them can hold copper. I would expect the phosphatic minerals to be the most "loaded" as far as copper release goes.
Once you get into fish-only systems, many of the assumptions that we make about reef tanks are probably untrue. For example, the buffer system in a fish-only system often bears little if any resemblence to an oceanic or reef tank. In the previous calculations, we assumed that the total alkalinity was coming mainly from dissolved bicarbonate and carbonate. Most fish tank buffers are loaded with other buffer substances, like borate and potentially organic buffers. It is quite possible for the carbonate alkalinity in a fish tank to be much lower than you would expect for a reef tank at the same total alkalinity. So from this effect alone, the pH values might shift up 0.3 or more pH units. (Again assuming that carbonates are the most relevant phase holding copper.)
For a direct answer to your question, yes, I absolutely believe that copper can "unpredictably" emerge from fish holding systems. I certainly believe that pH is the master control variable there, with contributions from carbonate alkalinity. People doing copper treatments often see swings in copper concentration, depending on what they are doing to the system.
Craig Bingman
<strong>Thank you for answering my earlier post about pH and Copper.
I should have told you why I was asking. I was not concerned with copper comming out of solution in a reef tank, but in a holding system. I use copper sulfate to treat parasites in a quarantine system. I have been told by many people that they believe that their fish died because the copper came out of solution in their marine tanks.
</strong><hr></blockquote>
As I said before, the problem is that we don't really know the chemical state of the material holding the copper. There are a number of minerals that can occur in detritial deposits, any one of them can hold copper. I would expect the phosphatic minerals to be the most "loaded" as far as copper release goes.
Once you get into fish-only systems, many of the assumptions that we make about reef tanks are probably untrue. For example, the buffer system in a fish-only system often bears little if any resemblence to an oceanic or reef tank. In the previous calculations, we assumed that the total alkalinity was coming mainly from dissolved bicarbonate and carbonate. Most fish tank buffers are loaded with other buffer substances, like borate and potentially organic buffers. It is quite possible for the carbonate alkalinity in a fish tank to be much lower than you would expect for a reef tank at the same total alkalinity. So from this effect alone, the pH values might shift up 0.3 or more pH units. (Again assuming that carbonates are the most relevant phase holding copper.)
For a direct answer to your question, yes, I absolutely believe that copper can "unpredictably" emerge from fish holding systems. I certainly believe that pH is the master control variable there, with contributions from carbonate alkalinity. People doing copper treatments often see swings in copper concentration, depending on what they are doing to the system.
Craig Bingman
