COPPER the potential hidden killer in a reef tank

[jeff@zina.com]

I think you seriously overestimate the amount of copper that can make it through a DI resin.

I think he seriously overestimates how much copper can leach from copper plumbing.

Without specific scientific data I'd call this a non-issue. Having dealt with EPA reporting in municipal water systems and having run tanks for more than three decades, I'd call it a non-issue even with specific data that seems to prove otherwise.

As for the rest of the discussion, Copper is rejected by the RO membrane. But the membrane usually has a rejection rate of 96-98% (or should) so you will still get some past it. DI resin catches all remaining copper ions. That's what the DI in DeIonization means.

There's an older, but still accurate, article by Randy Holmes-Farley on Reef Keeping that does a good job of walking through all this: http://reefkeeping.com/issues/2005-05/rhf/index.php

Plus this topic comes up regularly on Reef Central, use the Search options for more discussion.

Jeff

 

[GrahamJr]

I love Randy's Stuff. I read all of Randy's articles and I see nothing that truely contradicts anything that I have pointed out. In fact, it reinforces the copper issue with data and charts showing the copper content in our drinking water is very high.

"Lastly, some contaminants are more likely to come from the pipes in the aquarist's home than from the water supply itself. Consequently, these contaminants do not depend on the quality of the source water as much as the pH of the water and the nature of the pipes within the home. Many aquarists are fooled into thinking that their town has very clean water, so they need not worry about anything in their tap water. Unfortunately, that can be untrue. Chief among these that are of concern to aquarists is copper. Copper is allowed by the U.S. EPA to be present in drinking water at levels exceeding 1 ppm. Some homes in recent surveys have been found to exceed 1.3 ppm (Table 5)."

"Deionizing Resin Depletion Issues

Eventually, all of the H+ and OH- originally installed in a DI resin will become depleted, and ions will pass through unchanged (Figure 10). When charged ions begin to pass through the DI resin, the effluent's conductivity rises. Many RO/DI systems use an inline conductivity meter to alert users when ions are starting to appear, indicating that the resin needs to be replaced. Without such an inline meter, users need to periodically monitor the effluent's conductivity (in mS/cm or ppm TDS; details are given in the tips section on what conductivity to target for resin replacement).


Several issues arise relating to the depletion of the DI resins that aquarists need to be aware of. Primary among these is that when a DI resin becomes depleted, that does not simply mean that the water passes through just as it came from the RO effluent. It may actually be much worse from an aquarist's perspective. The reason for this is that while the DI resin is functioning properly, all ions will be caught. But when it is depleted, not only the new ions are coming through and might show up in the product water, but so are all the ions that ever got into the DI resin in the first place. The total concentration of ions coming out of the exhausted DI resin will not be raised as compared to the RO's effluent, but which ions are released may be very different."



The only thing thing I don't fully agree with Randy is that he used only his own experience and tank measurements of 10 to 15 ppb of copper to draw a conclusion that copper is not an issue. On the other he goes on to say that DI resin can become it own worst enemy if not renewed frequently enough because it will spew alot of what it has captured back into the tank.

Also Randy's own tank reading for copper is already too high. As I have also previously stated there is not any good accepted method method to get a good measurement of copper in ppb in a reef tank, because copper collects in many forms. Including inside the coral which it kills.

In addition, everyone also acknowledges that with normal tank pH and temperature swings can release copper that has been stored in the live rock, substrate, coral, and even the DI resin.

Again, I don't disagree with Randy's findings, if fact they support what I have said.

His conclusion about copper not being an issue is based on very limited comparative analysis of actual copper readings in only his own reef tank. Also the way the readings may have been taken to measure actual ppb copper content in the tank is not clear. He has said nothing to disclaim that just like phosphates, copper can build up in a home reef tank, to the point of overloading and poisoning the biological system. That was not the point of his article.

 

[AquaticFins]

Setting aside the issue of how much copper may make it through the RO/DI units...

In actuality, CupriSorb is nothing more than a weak acid cationic resin.

If we accept the premise that traditional DI cation resins do not effectively remove enough copper, why would CupriSorb be effective enough? Is there that much of a difference in the properties of the two resins?

I understand that it's supposed to be a "copper-specific chelating resin," but can it actually reduce copper levels down to single-digit ppb numbers in practical application if common aquarium DI resins cannot? If we're operating on the premise that significant amounts of copper are making it through traditional DI systems...I can't see how throwing a bag of CupriSorb in the sump is going to make any real difference.

I'm certainly not a chemist, so perhaps I'm completely misunderstanding the interaction of DI resins and ions, but it's not quite making sense to me. My understanding is that if a resin will exchange copper and there are still unexhausted exchangable ions in the resin, all of the copper should be removed (provided the flow rate isn't faster than the rate of exchange).

Is the thought that in practical application the DI resins are depleted of exchangeable ions so quickly that most people are not recharging their resin frequently enough to effectively remove enough copper to get their makeup water levels down to the sub-5ppb goal?

Is it a flow-rate issue? I would think multiple DI stages would effectively solve both problems.

Or is the idea that aquarium-use DI resins simply don't contain enough copper-specific (if such things exist) exchanging ions? Are DI resins actually specific to individual elements? I had thought polarity and charge were about the only things that mattered in terms of attraction (so a Cu 2+ ion and a Fe 2+ ion should treated roughly equally by a resin).

Forgive the questions, just trying to make sense of an interesting topic.

 

[GrahamJr]

Setting aside the issue of how much copper may make it through the RO/DI units..."¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦"¦...

Forgive the questions, just trying to make sense of an interesting topic.

You can't set aside the issue of how much copper may make it through the RO/DI units, because that is the whole point.

How many new reef keepers give up after 6 months or a year because of failure raising coral? I under stand copper poisoning is not the only potential problem. But it is one often totally over looked because it can happen so gradually and be so destructive. The fish are doing well but nearly all the coral show little growth or simply die.

I am trying to bring attention to the issue that copper concentration in our home water system is very high, thousands of time over the recommended levels for a reef tank. There are plenty of ways for that copper to get into and build up in our reef tanks. Copper poisoning can be fast, but it is often a very slow painful process in reef tank, first killing the bacteria, then the pods that feed on the bacteria,and then staving the coral that feed on the bacteria and the pods.

Many believe when they start that they don't need an RO/DI system. Many others believe they only need RO, like nuccadoc, who was under the false belief all he needed to do was keep the TDS meter reading at zero, because if it reads zero how can copper get into my system.

It isn't hard to understand why copper is and should be a better understood potential real issue. Most every home water system in this country have copper content of nearly a thousand times the acceptable limit for raising reef tank coral. If the home water chemistry changes by the water company, by water softening, or from stray electrical current issues, etc; copper poisoning issues can be much much higher.

Many long time reef keepers understand the importance of RO/DI and often install multi-stage dual, pre, and after filter systems. But even then, all it takes is being a little lack in it's maintenance, like changing out a spent DI unit or short circuiting in the unit, and copper intrusion can still quickly become an issue. Again keep the size of the numbers in mind"¦..we are talking about reducing existing copper content often by factors over a thousand. It is easy to screw up.

Copper poisoning builds up in the system, and slowy gets worse over time, as we add make up water. True copper content in the tank is very difficult to even measure. It gets absorbed into the live rock, substrate, coral and everything in the tank until it exceeds the systems ability to take any more.

I use Cuprisorb as a final polishing step"¦..is there a better or different way..probably..sure. That is not the point I am trying to make. I am trying to make reefers, old and new, understand copper is a reef tank issue that needs to be understood and addressed from the start as a very real potential problem.

 

[josephv]

imagine what all of our water goes through before it ever arives in our homes?All the years of going through what ever it goes through before it even comes close to your neighborhood let alone your house. Not to mention the waste water treatment that much of our drinking water under goes.Thankfuly pvc is used in much of the new construction in florida. Copper is and can be a problem but so is everything else. Bottom line is just because we are parinoid doesent mean that something isnt out to get us!!!

 

[BeanAnimal]

You've missed the point.

Graham, I think you may be vastly overthinking the point and yelling fire in the crowded theater...

Your Copper doomsday scenarios all require too many coincidental problems to be of any mainstream concern.

The bottom line is that for the vast majority of people using untreated tap or well water will likely cause other problems long before Copper poisoning ever comes into play. However, the point is moot, as the vast majority of serious reefers use RO/DI systems, so lets move on.

If we assume that the average RO/DI unit is only in marginal operating state and couple that with the fact that most water systems are really not suffering from significantly elevated copper concentrations then we still come out with the same conclusion, Copper poisoning introduced from the plumbing supply is really not an issue for most reefers.

If in fact your fears where well founded, there would be far fewer succesful reef aquariums and reports of copper poisoning (or tank crashes that illustrate the effects of copper poisoning) would be part of your regular daily reading.

Somebody mentioned it earlier... If you don't maintain a system, then the system is doomed to fail, no matter what it is.

You may wish to use the an extra copper absorbing resin as a fail-safe and there is no problem with that. From my perspective, I don't see the need for the average aquarist to do the same unless there is good reason to believe that there is subtantiated risk with the source water to their RO/DI system, and that RO/DI system is exposed to a high depletion rate due to high TDS and/or poor maintenance habbits.

Very interesting conversation, but from my perspective, Mt. Everest out of a mole hole.

 

[jeff@zina.com]

I am trying to bring attention to the issue that copper concentration in our home water system is very high, thousands of time over the recommended levels for a reef tank.

And I'm trying to bring attention to the fact that this isn't a fact. What proof do you have of typical, or even abnormal, aquariums having high copper levels, (where it actually matters, not in the overall system)? You've made an assertion that may or may not be true. Now you have to provide proof or it's just a random theory.

In my case, anecdotal and unscientific evidence would prove otherwise. Given scientific evidence I'd be happy to re-evaluate my position. I simply can't find any, perhaps you can.

The bottom line would be a causal link between high copper levels in a home water system and corals dying. The best thesis would be a solution to this issue, if it exists. I'm just glad I'm no longer a grad student.

Jeff

 

[jason2459]

I've never seen a carbon of any type that could remove copper or any other metal from water, and I've worked in the water processing field for over 15 years. The RO system alone is sufficient to remove copper and when used in conjunction with DI resin it is more than effective....

I thought GAC was effective at removing copper? Pretty much all copper based medications says to remove carbon while treating and to add it back in to help remove the copper?

 

[BeanAnimal]

Hrmm... Indeed an interesting idea for a thesis!

As for GAC and COPPER...
Here is one refernce, I am sure there are more that can be found (if not contradictory for that matter)
http://uotechnology.edu.iq/tec_magaz/volume272009/No.12,2009/researches/Text%20(8).pdf

And only partly relevant but interesting read nonetheless:
http://www.h2oc.com/pdfs/Cu3.pdf

 

[jeff@zina.com]

There's a difference between (most) copper medications and just copper ions in water, and charcoal will usually remove most medications. Skimming also takes some out as well. The major issue isn't medications, it would be copper ions attaching to the existing substrate, rock, whatever in the tank and building up.

To be clear, I'm not saying that the theory isn't sound. It's just unproven and all the current anecdotal evidence points to it being a non-issue. I'm now wondering if this could be a simplified experiment, or set of experiments, but you need a lab that can measure copper in PPB, and those aren't cheap.

Jeff

 

[GrahamJr]

I just realized something during this discussion. Let me make a simple comment and observation about the efficiency of the DI resins and filters I use in my reef systems. The comments by many have been that the DI filter, after the RO, will efficiently capture any copper carry over and what is not removed with the RO.

I have said that for various reasons I do not beleive that to be true. And that we should be concerned that copper can bypass and/or short circuit a rather simple DI container filled with resin. What is the imperical proof of my comments that we should be concerned about copper entering our tanks even when we use RO/DI?

I have my personal RO/DI set up with six stages. Prefilter-Fine Carbon(chlorine removal)-RO-Carbon(2)-DI(1) and DI(2). In my DI containers, one and two, I use the color changing resin so I will have a visual indication of it's condition, in addition to measuring with a TDS meter.

If the DI(1) was as efficient as some have stated they believe it is, and it removes 100% of what is left after the first four stages, the second DI(2) I have in series would not start to change color until the first DI was close to or 100% spent.

The fact is my second DI(2) starts to show some indicating color change soon after being installed, and it is indicating considerable color change well before the first DI(1) is indicating only 50% spent. The only way this could happen is from internal fluid short circuiting within in the first DI(1) or a lower than 100% capture efficiency of the new resin.

RO/DI is not 100% efficient even with fresh filters and carbon, as we would like to believe, and even less when comes to removing anything in ppb. When you consider we need to remove copper with an efficiency of one thousand times more than we can even measure with TDS meter, to truely keep our tanks even close to as being copper free as a natural reef……I still think we still have a lot to learn about reef keeping and the potential negative effect of copper.

I believe it pays to error on the conservative side on this topic. I'll continue to polish my RO/DI water as I refill my make water containers.

 

[billsreef]

I thought GAC was effective at removing copper? Pretty much all copper based medications says to remove carbon while treating and to add it back in to help remove the copper?

Many coppers, such as cuprimine, are complexed and easily removed with carbon. Straight ionic coppers are less susceptible to being removed, but still can be removed to large enough extant by carbon to effect the dosage necessary for treatment.

In regards to how much copper is too much in a reef aquarium, there is huge body of very successful tanks and coral aquaculture operations that show tank levels can indeed be higher than NSW without issue. Basically any SW made with artificial salt mix will have substantially (when thinking in terms of ppb) higher copper levels than NSW. So the question really becomes how much copper in a closed system is acceptable the organisms we keep, not how much copper is in NSW.

 

[GrahamJr]

Many coppers, such as cuprimine, are complexed and easily removed with carbon. Straight ionic coppers are less susceptible to being removed, but still can be removed to large enough extant by carbon to effect the dosage necessary for treatment.

In regards to how much copper is too much in a reef aquarium, there is huge body of very successful tanks and coral aquaculture operations that show tank levels can indeed be higher than NSW without issue. Basically any SW made with artificial salt mix will have substantially (when thinking in terms of ppb) higher copper levels than NSW. So the question really becomes how much copper in a closed system is acceptable the organisms we keep, not how much copper is in NSW.

Excellent points. Two things you are not considering. 1) The continually increasing copper concentration from evaporation if our make water contains more copper than is acceptable to the organisms. 2) If the excess copper is being bound in the live rock, substrate, and the organisms; what will happen if a pH or temperature swing, or other flux, causes the copper to go back into the water column in a higher concentration.

This has always been the discussion around the detrimental effects of phosphate bound up in the live rock and substrate, and a potential cause rapid death in established reef tanks.

 

[disc1]

I just realized something during this discussion. Let me make a simple comment and observation about the efficiency of the DI resins and filters I use in my reef systems. The comments by many have been that the DI filter, after the RO, will efficiently capture any copper carry over and what is not removed with the RO.

I have said that for various reasons I do not beleive that to be true. And that we should be concerned that copper can bypass and/or short circuit a rather simple DI container filled with resin. What is the imperical proof of my comments that we should be concerned about copper entering our tanks even when we use RO/DI?

I have my personal RO/DI set up with six stages. Prefilter-Fine Carbon(chlorine removal)-RO-Carbon(2)-DI(1) and DI(2). In my DI containers, one and two, I use the color changing resin so I will have a visual indication of it's condition, in addition to measuring with a TDS meter.

If the DI(1) was as efficient as some have stated they believe it is, and it removes 100% of what is left after the first four stages, the second DI(2) I have in series would not start to change color until the first DI was close to or 100% spent.

The fact is my second DI(2) starts to show some indicating color change soon after being installed, and it is indicating considerable color change well before the first DI(1) is indicating only 50% spent. The only way this could happen is from internal fluid short circuiting within in the first DI(1) or a lower than 100% capture efficiency of the new resin.

RO/DI is not 100% efficient even with fresh filters and carbon, as we would like to believe, and even less when comes to removing anything in ppb. When you consider we need to remove copper with an efficiency of one thousand times more than we can even measure with TDS meter, to truely keep our tanks even close to as being copper free as a natural reef"¦"¦I still think we still have a lot to learn about reef keeping and the potential negative effect of copper.

I believe it pays to error on the conservative side on this topic. I'll continue to polish my RO/DI water as I refill my make water containers.

But with all the different things in the water, and the high affinity of copper to the resin, what makes you think that the breakthrough would have any copper in it?

Like in the RHF article. If the media is exhausted, it will trade ions with low affinity for those with high affinity and things start coming off into the water.

Now is copper one of the things getting turned loose, or is copper one of the things that is displacing other ions? Copper has a high affinity for the media. So even with an exhausted DI stage, it's still going to be hard to get copper through. You'll lose the lower affinity cations first.

 

[disc1]

And, while talking about short circuit or channeling in the media you also need to think about transit time and diffusion. Copper diffuses fast compared to other ions. The water in the DI chamber is not flowing laminar. So between the turbulence and the diffusion, most ions are going to have a chance to come into contact with the media. Now, again, it becomes a question of affinity, and copper has a pretty high affinity.

 

[GrahamJr]

And, while talking about short circuit or channeling in the media you also need to think about transit time and diffusion. Copper diffuses fast compared to other ions. The water in the DI chamber is not flowing laminar. So between the turbulence and the diffusion, most ions are going to have a chance to come into contact with the media. Now, again, it becomes a question of affinity, and copper has a pretty high affinity.

Parts per billion of copper will not even get through a spent DI filter because of its high affinity. Great theory and has merit. I think that would be a very interesting experiment for you to run. Let me know the outcome. Until then, I'll keep polishing.

 

[BeanAnimal]

Curious as to what you propose to do about the copper that may enter through the salt mix, food and other items imported into the aquarium as well as the other metals that may or may not be imorted or make it past the RO/DI stages that your concern outlines?

 

[disc1]

Parts per billion of copper will not even get through a spent DI filter because of its high affinity. Great theory and has merit. I think that would be a very interesting experiment for you to run. Let me know the outcome. Until then, I'll keep polishing.

I don't need to run any experiment. I posted a real good paper where it had already been done.

I'm not saying that there's zero chance of copper breaking through a DI chamber. I am saying that you are way overestimating how much is going to come through. You are completely ignoring the chemistry here. Just because you don't understand it doesn't mean it's not real.

 

[disc1]

And on the topic of chemistry, if it does make it through the DI stage, then what are you going to do about it?

Cuprisorb in the tank can't be a bad idea. Copper and other heavy metals come from a great many other sources.

Cuprisorb on your RODI effluent is about as useful as a screen door on a submarine. It doesn't work well at low to neutral pH. That's just the chemistry.

 

[disc1]

I'm not saying that copper isn't toxic or that you shouldn't watch out for it. All I am saying is that a properly functioning well maintained RODI is your best line of defense.