Copper absorbs into glass...no...

[cichlidfort]

I just read a thread in the archives on how copper absorbs into glass. This is this possible.

Copper does not absorb into glass.

I have a hard time believing that.

[leebca]

It's a bit of a stretch for me, too. And I'm a chemist.

The matter has been put forward by a moderator in Reefland, Ninong. His post near the middle of this thread says it:
Snails and hermits dying!

Ninong links to this thread:
Coverting from freshwater tank to saltwater

I have no first-hand knowledge of this phenomena. I guess it can be easily proved or disproved. Just run glass with a copper medication for a normal treatment cycle (14 days?), rinse out, wash out, then set in deionized water that was test for copper ions. After a few weeks, check the container for copper. In the parts per billion range indicated lethal to invertebrates by Dr. Shimek, an appropriate analytical process can be used.

But if copper ions (a relatively small ion) can go into glass, then why not sodium, magnesium, potassium, etc.?

The only experience I had was with an aquarium I set up just two years ago. Everything was going well. I was having the water analyzed by a laboratory that routinely analyzes seawater. Copper was one of the elements being watched. Then suddenly, without warning, 90 ppb copper showed up! I performed water changes and put in fresh carbon and even specialized copper absorbing chemicals.

It took two weeks for the copper to reach undetectable levels. Where it came from, I still haven't a clue. Maybe one or more of the rocks leached it out? Anyway, during this time the invertebrate population didn't die back as far as I could tell. You see, the only things in the tank at that time were invertebrates. In fact some snails were laying eggs during this time, which later hatched and are still living. They were common inverts, from turbo snails, Fighting Conch, bristle worms, Nassarius, and a large population of copepods to micro stars, a sea hare, and various small shrimps.

[cichlidfort]

I don't get why Ninong says copper is absorbed into glass? Since when has glass become microporous? If glass is microporous is acrylic?

I have a hard time believing copper gets absorbed into glass because I have used copper medications in the past on my 55 freshwater. That 55 freshwater is now a saltwater with all kinds of inverts including corals. There are no signs of copper or unhealthy inverts.

Even if somehow copper were to leach out into the water in such small amounts where test kits can't pick it up it wouldn't affect the fish since small amounts of copper naturally occur in the ocean. Copper test kits are generally used to measure copper levels when aquarists are using medications involving copper not when they are trying to detect small amounts.

There is another thing I don't get either. If glass could absorb copper then why doesn't it absorb water? Why doesn't it absorb magnesium or strontium?

There still seems to be some flaws and lack of logic in this arument in my opinion.

[Ninong]

I would like to point out that I have never said copper is absorbed by glass. Glass is not permeable. What I have said is that copper is adsorbed on glass. That's a well known fact.

I suggest you look it up in the scientific literature. I googled "copper adsorption on glass" in the scholar search function and came up with these hits; using book search, I came up with these hits.

P.S. -- I just noticed that Dr. Randy Holmes-Farley has written that copper IS absorbed by glass but very slowly. He also states that it is quickly adsorbed on glass. So I guess it is possible for copper to be absorbed by glass to some extent over time. I'm not about to disagree with Randy on matters of chemistry. I had only two years of college chemistry and that was half a century ago.

[cichlidfort]

Wow, adsorbed. Missed that small detail.

But still, there are still gaps in your logic. Your basically saying that copper forms a molecular bond with glass to form a film that can be potentially deadly to inverts if released. However, I have used copper medications on my tank and now look what I have. Nothing has died.

Even if small amounts of copper were to be released. Like I said its not going to affect anything really since copper does naturally occur in the wild. If it can't be picked up on a test kit, then how is it going to be a problem? Copper test kits are used for measuring massive amounts of copper in a tank, usually a hospital tank.

[Ninong]

The concentration of copper in the ocean is 0.000254 ppm (0.254 ppb). Obviously at that level it is not harmful to anything, so why anyone would point to this is beyond me. To put this in perspective, that's the same as saying 1-1/2 people out of the entire population on Earth. Current world population is approximately 6 billion.

Copper is harmful, even lethal, to some invertebrates, especially mollusks, at levels as low as 2-5 ppb. Note that that level would be 10 times NSW levels. It is not harmful to fish at these low levels. It is harmful to fish in the low ppm range. That's ppm, not ppb.

Test kits cannot detect copper in the low ppb range. Test kits are designed to detect copper in the range that it is commonly used as a therapeutic for fish. Cupramine, for example, is recommended at 0.5 ppm to treat marine ich. However, if you let the copper level rise to say 5 ppm, you could end up killing your fish.

Usually the copper that is adsorbed to glass tank walls and then subsequently released into the water column is in the ppb range, not the ppm range. However, this is enough to kill off snails, polychaetes, and some other sensitive inverts. When fish are killed, it is usually caused by something like brass plumbing fittings and not adsorbed copper.

[Ninong]

If it can't be picked up on a test kit, then how is it going to be a problem?

Copper is lethal to some invertebrates at levels 1,000 times less than what can be detected by typical test kits. It is lethal in the low ppb range. Most test kits can only measure in the ppm range, although I believe there are a couple that claim to be able to measure down to 50 ppb. How accurate they are at that level is anybody's guess.

[Ninong]

Even if small amounts of copper were to be released. Like I said its not going to affect anything really since copper does naturally occur in the wild.

Your statement makes no sense whatsoever. Why do you keep repeating the fact that copper occurs in the wild at 0.000254 ppm (0.254 ppb). Of course it's not a problem at that level. It's a problem only when it gets about 10 times that level and only to certain inverts, not fish. It has to be much higher than that to become a problem for fish. However, even the low levels (~0.5 ppm) that are used to treat fish can have deleterious effects over time. Low levels of copper damage the fish's immune system and it's reproductive system. This is why Scott Michael, who once used copper, no longer uses it for anything. He considers its harmful effects outweigh any possible benefits.

[cichlidfort]

Alright, well why is it not effecting me? I have used copper in the past within a year and now I have inverts.

When I said "Even if small amounts of copper were to be released. Like I said its not going to affect anything really since copper does naturally occur in the wild"

I was referring to the small amounts being released such as to the wild. I am sorry I wasn't being specific enough.

Also, why did you say you have to remove all the liverock and sand when a tank has been "contaminated" with copper. Since when does copper adsorb into rock?

Now that doesn't make any sense at all..................

[Ninong]

Since when does copper adsorb into rock?

Now that doesn't make any sense at all..................

Of course copper adsorbs onto rock. It adsorbs onto the sediment, too. In fact, it adsorbs onto all surfaces in the system. This isn't exactly rocket science.

Whether it causes problems later depends on a lot of factors, including the amount that was adsorbed and the rate of release (desorption). Again, it is not likely to cause harm to fish but it could very well cause harm to inverts.

The EPA requires that all glass vessels and implements be washed with hydrochloric or nitric acid and then rinsed several times with distilled water before conducting copper toxicity tests.

If you didn't already read Dr. Ron Shimek's comments on this topic that I included in my previous post, then you can find them here. Dr. Shimek managed the Friday Harbor Lab at the University of Washington for some 14 years.

[leebca]

Sorry Ninong. I missed the "d" also. The mind plays tricks.

If it's adsorbed, then it is on the surface? Why wouldn't/couldn't it be easily dissassociated? It doesn't seem it would take all that much to get it to 'let go.'

[Ninong]

Lee,

Dr. Randy Holmes-Farley, who has a doctorate in chemistry and is a vice-president of Genzyme, addressed that question in this Reef Central thread.



P.S. -- I googled "copper adsorption on glass" and came up with these hits using Book Search and these hits using Scholar Search.

[leebca]

Still wondering. . .

If the adsorption is that 'strong' then why is there a concern it will enter back into the seawater again? And if Poly Filter, carbon, or other treatments are run routinely, how much of a problem would it be?

[Ninong]

According to what I have read in posts by Dr. Randy Holmes-Farley and Dr. Ron Shimek over the past several years, copper is adsorbed to all surfaces in the system while copper is being added to the system. After you discontinue adding copper to the system, the adsorbed copper is gradually desorbed over time. I assume fluctuations in pH, alkalinity, etc., have something to do with this but I'm not sure.

Obviously running polyfilters continuously would mitigate this potential problem. I don't know if it would eliminate ALL risk or not. Don't forget, we're talking about an extremely small concentration that can be dangerous for some inverts. One to two parts per billion is like 6-12 people out of the entire population on Earth.

You could ask that question of Dr. Shimek in his Marine Depot forum or you could send him a PM on Reefland. He is a regular contributor to our online magazine, Reef Hobbyist Online, and is now a registered member of the board, too.

[leebca]

Thanks Ninong.

I suspect you are correct about the low levels being an issue.

Thanks. I'll follow up with both people you mentioned.

[Ninong]

Lee,

Ron would prefer that you either post to his Marine Depot forum or send him a PM through Reefland.

[greenbean36191]

Also, keep in mind that the harmful effects of copper on inverts are cumulative. A concentration of 2 ppb might be deadly, but death won't be quick. It will take a while for it to take its toll. Just because inverts aren't instantly killed by a given concentration of copper doesn't mean it's a harmless level.

[cichlidfort]

I have never heard of it absorbing onto the rocks.


That seems rediculous

[leebca]

That might depend upon the composition of the rocks. Different materials might even react with copper.

I suppose though there are millions of things I haven't heard of.

[Ninong]

Lee,

Dr. Randy Holmes-Farley touches on the copper toxicity issue in his discussion of toxic metals in tapwater here.

And I would like to remind everyone of the excellent point that greenbean raised and that is that the harmful effects of copper on inverts are cumulative. Even if you don't see any acute symptoms and sudden dieoff, that doesn't mean your inverts are suffering from chronic copper toxicity that takes a little longer to kill them.