What you need to know about copper and coral

[Randy Holmes-Farley]

Thanks.

Some of that is wrong, like the parts on salt mixes having high copper and how that was tested, but they clearly do add copper and such into the Poly Filter still.

Whether it comes out or not in reef tank water with low copper is perhaps an open question, but if it does not then their whole rational for equilibrating raw polyfilters with artificial seawater prior to use doesn't make sense to me. If it is not an equilibrium process, then simply occupying some of the sites with trace metals won't impact its ability to further bind more metals into still available sites to levels below that present in the equilibrating seawater, which is the stated reason for doing it.

Note that they do not address that organics in reef tank water might be as good or better chelators than their media and may strip it away. That's a very different scenario than pure fresh water or artificial seawater.

[HighlandReefer]

Thanks Randy.

I have sent another email for any response to your concerns. I have encouraged Poly-Bio-Marine, Inc. to post directly here in this thread if they like.

I too am interested in any response they may have regarding the questions you have posed.

[Randy Holmes-Farley]

Well see.

[Randy Holmes-Farley]

FWIW, there appears to be another good way to possibly and routinely remove copper from reef aquaria, but I cannot say anything until the experiment that I reviewed today for someone else is published.

[disc1]

Originally Posted by Randy Holmes-Farley

FWIW, there appears to be another good way to possibly and routinely remove copper from reef aquaria, but I cannot say anything until the experiment that I reviewed today for someone else is published.

Tease...

[HighlandReefer]

[tmz]

That would be a big help .

[Randy Holmes-Farley]

Patience....

[Randy Holmes-Farley]

So just to make sure folks understand my position on some of these products...

First, any copper detectable with a test kit is likely too much. For a healthy reef tank, you will not be able to monitor copper levels with a kit at low enough levels with sufficient reliability. In accidents (like a spill of fish med into the reef tank) or fish treatments (as in a hospital tank), however, you can often detect copper with a kit.

Cuprisorb and Polyfilters are booth seemingly a good way to deal with substantially elevated copper levels. I've recommended both hundreds of times. There are likely also other ways that work, but as of today, these are good choices for that application.

If you have what I consider "normal" reef aquarium levels of copper, and by that I mean maybe 5-30 ppb and you want to lower copper further, I would not use a Polyfilter because the manufacturer preloads them with copper (and other ions) sufficient that by their own claims, it won't reduce copper further. Whether it adds any to the aquarium in that context is debatable and, at present, unknown to me, but it is clear it should not remove any as that was the reason for the manufacturer to copper to Polyfilters in the first place.

Cuprisorb may be a similar (or identical) product for which they do not make any claims about preloading them with copper (that I have seen), and Cuprisorb may function for the purpose of lowering copper below 30 ppb, although I've not seen any data suggesting it will (or won't). If very low copper levels are a goal (say, 5 ppb), then Cuprisorb would probably be my recommendation at this point.
Exporting organic matter in a variety of ways, such as by skimming, will help export copper, and I think many of these methods can be useful. It is not clear, however, how effective that will be overall.
In my careful testing of my reef aquarium water a few years ago, I detected about 10-15 ppb copper in my tank using no special means for copper export aside from normal skimming (and, IIRC, using GAC). In an identical test of the Instant Ocean I used as a salt mix at the time, I detected none, which in this case means less than 10 ppb or so.
This article details a number of thoughts relating to trying to keep an aquarium with low metals:
Reef Aquaria with Low Soluble Metals
http://reefkeeping.com/issues/2003-0...ture/index.php

[HighlandReefer]

Thanks for the summary Randy. It is difficult when all the necessary information is not disclosed by manufacturers to help make the best decision as to which products would be useful to hobbyists and in which scenarios.

I would like to point out that very few manufacturers have cooperated with us like Habib (owner of Salifert) has in the past. I assume some of Salifert's success may be credited to this. After all a little sugar goes a long way.

[disc1]

What method did you use to test the water in your experiment Randy? Just out of curiosity.

[Randy Holmes-Farley]

I used an ICP-OES in the same way that I tested some supplements in this article:

Purity of Calcium Chloride
http://www.advancedaquarist.com/issues/mar2004/chem.htm

Such testing needs to be done carefully. I've sometimes been concerned with studies by folks who do such work who just send samples out for lab analysis (even "official" methods), and do not even double check to see whether the answers they get are within the limits of accurate quantitation of the device, or if none is detected, what that means, and in some cases, the answer might even just be integration of noise or interference due to other ions.


Here's a discussion of what I did:


ICP Testing Methods


There has recently been a significant amount of discussion in the hobby concerning analytical methods. Richard Harker has recently authored two articles that demonstrate some concerns with a particular method involving ICP (Inductively Coupled Plasma; Article 1, Article 2). In this technique, the liquid sample is injected into an incredibly hot plasma, completely breaking the sample down into individual elemental ions. There are a variety of ways to then detect these ions, including mass spectroscopy (called ICP-MS) and from the intensity of different wavelengths of light emitted from the different ions (called ICP-OES, with OES standing for Optical Emission Spectroscopy).

I have chosen to use ICP-OES, largely because it is the instrument that I have available (A Varian Vista-MPX). It is also the method that Richard Harker has claimed to be problematic when using a particular protocol (ICP Scan, EPA method 200.7). I share some of his concerns about the use of ICP, particularly for ions that are near their detection limits. In fact, I believe that some analyses reported in the aquarium literature using ICP-OES may simply reflect instrumental and sample noise that was added up by the software used with the instrument to report an artificially high value. I have discussed this concern in the past, for example, for aluminum.

In all ICP-OES data that I have presented in prior articles, as well as all data in this article, such issues are not a consideration for the reader. I have carefully looked at the emission data for each ion and for each sample, with my own eyes, to confirm whether the data claimed by the software is a real emission, or just noise. For all signals near the noise level, I spiked small but known amounts of commercial ICP standards into these calcium chloride solutions to see exactly how high of a concentration would have to be present in these solutions to be able to see real signals. These detection limits are often different than the detection limits stated by the instrument manufacturer (since those stated values do not take into account the nature of other interfering ions in your test sample, such as a huge background of calcium and chloride), and are shown later in the article. I have also tested the highly purified water used to dissolve the solid samples in this study. This type of protocol takes much more effort than running the sort of ICP scan that Harker has discussed. Nevertheless, it is important when trying to understand the limits of the data obtained.

This process is shown in Figure 1. Figure 1 is a plot of the emission intensity in one of the wavelength regions expected to have emissions from cadmium. The bottom spectrum in Figure 1 is part of the emission from the Dow sample. There is no apparent peak at 228.802 nm where one expects one of the emission peaks for cadmium. However, when 0.1 ppm cadmium is added to this sample (top spectrum in Figure 1), the cadmium emission is clearly seen. Adding 0.02 ppm Cd instead of 0.1 ppm results in a smaller, but still clearly defined peak above the background noise. From those results, I conclude that the Dow sample has less than 0.02 ppm cadmium.



Figure 1. Emission spectrum in the region of one of the emissions from cadmium. The bottom curve represents the emission from the Dow sample. The upper curve represents this same sample spiked with 0.1 ppm cadmium. The H-shaped symbol in the middle represents the region actually integrated to collect data (between the vertical lines).


Figure 2 shows the cadmium emission from the Kent Turbo Calcium sample. Even without any extra cadmium added, it has a clearly defined cadmium peak at 228.802 nm. When that peak area is compared to cadmium standards, I conclude that it has about 0.07 ppm cadmium. This process was repeated for 2-3 emission peaks for each ion and for each sample. The tabulated results represent an average of these values for each ion. Table 1 shows the limits of detection that I determined using the above process for many of the ions tested in this article (for most of the other ions, the limit of detection was far below the values found).



Figure 2. Emission spectrum in the region of one of the emissions from cadmium for the Kent Turbo Calcium sample. The H-shaped symbol in the middle represents the region actually integrated to collect data (between the vertical lines).


In short, and summarized for folks that do not have much interest in instrumental methods:

Note: The data in this article do not suffer from any of the complications previously discussed by Harker and others relating to ICP, and can be considered reliable indications of what was present in the samples tested.

[Randy Holmes-Farley]

For more info on copper specifically, I showed the wavelengths I used for the the ICP-OES in a previous article on limewater self purification and presume I did the same on my tank water:


http://reefkeeping.com/issues/2003-0...ture/index.htm

I monitored copper concentrations using a modern analytical lab technique: Inductively Coupled Plasma (ICP) using atomic emission detection. I used two different emission peaks (324.754 and 327.395 nm).

The use of multiple wavelengths was how I got a slightly better limit of quantitation than the machine qoutes (it claims 20 ppb). I could easily see a 10 ppb peak, but could not see a true peak below that. For my tank I saw clear peaks a bit bigger than the 10 ppb standard but below the 20 ppb. There was no clear peak in Instant Ocean.


My low metals article I posted above has a statement about the amount I found in my tank (10-13 ppb).

http://reefkeeping.com/issues/2003-0...ture/index.php

but at this moment I cannot find the first place I reported the copper levels in my tank and the details of doing so.

[HighlandReefer]

For my clarification Randy.

These tests run for copper and the results given are for Total Copper (including organics)?

[Randy Holmes-Farley]

Yes. Anything in the solution in any form gets converted into individual atoms/ions in the super high temperature of the plasma.

[jeremy K]

I just heard back from Seachem regarding Cuprisorb. Here's what they say about it:
"Unlike many competing filter medias, like the polyfilters, Cuprisorb is designed to remove any copper present. As long as the product is not exhausted, it should continue to remove copper, including trace levels. This makes it a great product for removing copper after medication or in the case of high concentrations in source water. However, if it were to be left in the system permanently to keep these levels under control, it would be a good idea to add a trace element package to ensure that the habitants had some trace levels of copper available. While copper is toxic to many marine organisms at high levels, it is essential for all organisms and should be maintained at trace levels. Please let us know if you have any additional questions. "

Product Support
1080

[HighlandReefer]

Jeremy,

Thanks for the post.

[Ink]

All these information are very interesting, but do You really think Cu could be a problem in our aquaria? Except cases when there is some unwanted piece of copper in our tanks poisoning our water...

many aquarists regularly add CuSO4 using various commercial products to reduce zooxanthellae without any issues (i.e. zeospur KZ, nuance equo).
I know aquarists have been doing this since years without loosing any animal...
I think regular water change ad constant use of GAC is a need in this case.

In the last times I read something about metal binding to organic in marine water and the informations You provided confirms why these products must be added in one shot (I mean not dividing in many administrations), not repeat before 15-20 days, and the lower are inorganics (and i guess organics too), the lower is the needed dose of product. If inorganics are too high, there is substantially not enough dose to make effect...

On the basis of this last affirmation, I think Cu could eventually be more problematic in ULNW tanks.

[HighlandReefer]

The scientific studies are overwhelming regarding the detrimental effects copper can have at very low levels. Is this possible in a reef tank? IMHO, yes depending on the unmeasurable levels of copper input and the total amount of unmeasurable dissolved organic matter in reef tank water as well as the coral specie types and their types of symbionts present.

When Randy tested his tank, his copper came out to around 13 -15 ppb copper.


Differential effects of copper on three species of scleractinian corals and their algal symbionts (Symbiodinium spp.). (2010)

Bielmyer GK, Grosell M, Bhagooli R, Baker AC, Langdon C, Gillette P, Capo TR.

http://www.ncbi.nlm.nih.gov/pubmed/20089320


Abstract

"Land-based sources of pollution have been identified as significant stressors linked to the widespread declines of coral cover in coastal reef ecosystems over the last 30 years. Metal contaminants, although noted as a concern, have not been closely monitored in these sensitive ecosystems, nor have their potential impacts on coral-algal symbioses been characterized. In this study, three species of laboratory-reared scleractinian corals, Acropora cervicornis, Pocillopora damicornis, and Montastraea faveolata each containing different algal symbionts (Symbiodinium A3, C1 and D1a, respectively) were exposed to copper (ranging from 2 to 20microg/L) for 5 weeks. At the end of the exposure period, copper had accumulated in the endosymbiotic dinoflagellate ("zooxanthellae") and animal tissue of A. cervicornis and the animal tissue of M. faveolata; however, no copper accumulation was detected in the zooxanthellae or animal tissue of P. damicornis. The three coral species exhibited significantly different sensitivities to copper, with effects occurring in A. cervicornis and P. damicornis at copper concentrations as low as 4 microg/L. Copper exposure affected zooxanthellae photosynthesis in A. cervicornis and P. damicornis, and carbonic anhydrase was significantly decreased in A. cervicornis and M. faveolata. Likewise, significant decreases in skeletal growth were observed in A. cervicornis and P. damicornis after copper exposure. Based on preliminary results, no changes in Symbiodinium communities were apparent in response to increasing copper concentration. These results indicate that the relationships between physiological/toxicological endpoints and copper accumulation between coral species differ, suggesting different mechanisms of toxicity and/or susceptibility. This may be driven, in part, by differences in the algal symbiont communities of the coral species in question."

[HighlandReefer]

There are many cases where hobbyists state that they are experiencing coral tissue necrosis. The reasons for this are blamed on many possibilities and rightfully so, since there are many things that will cause tissue necrosis in coral. Certainly higher levels of copper can't be discounted in these cases.

The same applies when hobbyists have problems with coral that have lost their color.

It is pretty much impossible for hobbyists to discern these types of problems in a reef tank for sure.

[HighlandReefer]

FWIW, EPA in 2003 established the safe copper level in and around reefs as 3 ppb. I think many of our tanks may have higher levels of copper.

I'm not quite sure where the common recommendation for the copper level in reef tanks is stated as less than 30 ppb.

[Randy Holmes-Farley]

It may have come from the limit of testing capability with certain analytical methods.

[Habib]

Did the point of view change that if it is not bioavailable it is not a problem?

[HighlandReefer]

I just read the complete article above. The tests were completed using inorganic copper as CuCl2. As far as I know, the organic copper is not very toxic.

The studies do show that if the inorganic copper is high enough even for short periods of time, damages occur & show up within hrs in coral.

The question is what are the highest inorganic copper levels in one's reef tank and do they reach toxic levels?

Good point Habib.

[HighlandReefer]

Habib,

I know you did quite a bit of research to write your article:

Feature Article: Toxicity Of Trace Elements: Truth Or Myth?
http://www.advancedaquarist.com/2003/5/aafeature

What is the break-down between inorganic and organic copper on average say in the ocean. Something comes to me that it is in the area of 90-98% organic copper?

Perhaps that's where they get the recommendation of 30 ppb copper as total copper.