It doesn't seem Heavy metals are the cause

[gregt]

Thanks for the effort of doing the assay. I'm sure the wife is very happy that it is done.

I'm having trouble with your conclusion that heavy metals are responsible for the survival results in your assay.

The two salts that made artificial seawater with the lowest survivorship of larvae consistently have heavy metals concentrations hundreds to hundreds of thousands times those found in natural seawater.

Perhaps I'm missing something but let me explain my confusion.

If I understand correctly, your conclusion is based on the fact that there is a correlation of survival rates to heavy metal concentrations. This would seem obvious when comparing NSW and the artifical mixes. There is significantly larger amounts of heavy metals in the mixes and likewise a significantly lower survival rate in the assay. Based on that it is logical to suggest that heavy metals are a likely causative agent.

However, if you use the same criteria in comparing the two commercially available artificial mixes (IO and coralife), you come to the inverse conclusion. IO, in fact is lower in all metals except Manganese, Potassium, Sodium, and Strontium, of which none are the commonly "worried about" metals. Despite this, the survival rates of IO are roughly half that of Coralife, which is not what I would have expected if heavy metal concentrations are causative. I would have expected them to be similar or IO to have a worse survival rate.

This suggests to me that there is more at work here than simply heavy metals.

Do I find the levels of heavy metals in our salt mixes acceptible? Absolutely not, but based on my own personal experience with one of the commercial salts involved, I'm not quite ready to change my salt brand yet.

Any comments are appreciated,

 

[rshimek]

Hi Greg,

There is no discernable difference between the survival rates in IO and Corallife (they are not statistically different), so regardless of the absolute survival, we have to consider them as being the same.

Both of these salts are effectively heavy metal cocktail mixes.

Strontium has been documented in the scientific literature to poison corals, but it is a weak poison, and probably doesn't kill them unless present in very high doses. The others you mentioned may have some effect but are not generally considered to be toxic.

Almost of the heavy metals have been demonstrated to kill either corals or other inverts at concentrations far lower than are found in the mixes.

This correlation indicates, to me, that the metals are the cause.

However, this is a correlative study, and perhaps some other factor is in play. After all, one can not use correlation to prove or disprove anything.

It would take extensive and expensive testing to pin down the specific chemical actors in this drama, but I suggest that the smoking gun certainly points to excessive heavy metal concentrations.

 

[gregt]

I understand everything in your response and agree with almost all of it, especially this:

Both of these salts are effectively heavy metal cocktail mixes.

However, I don't understand how you determine that a survival rate differential of a factor of two to be "indiscernable".

I'm also not ready to reject my years of success with this particular salt as I've not had a death not attributed to a mistake in husbandry in over 4 years using this salt, so understandably, I'm not easily convinced that it's certain death, so to speak.

 

[WaterKeeper]

Greg,

I have been one of the advocates for water changes in various threads in this forum. Doc Shimeks latest bioassay results have thrown some doubts in my mind of the quality of IO, which is the salt I use. I, like you, have not seen any harmful effects in my tanks from using IO but there was pretty solid evidence in this latest article that IO has a negative effect on certain marine invertebrates.

The purple urchin is used in many studies and has a known susceptibility to low levels of toxicity. In that regard it is like Cerio Daphnia Dubia used in fresh water bioassays. I have heard laboratory people using this daphnia exclaim it dies if one utters a disparaging word . I would like to see some further evidence such as a bioassay using Mendia Beryllina, the inland silverside. They are more tolerant of heavy metals than Arbacia.

Overall however, I found this latest article very revealing and hope the manufacturers of artificial salt mixes will take heed. Even if it's not a problem with "heavy" metals it appears that something in the IO and Corallife mixes had an adverse effect in this study.

 

[rshimek]

Originally posted by gregt

Hi,

However, I don't understand how you determine that a survival rate differential of a factor of two to be "indiscernable".

The means differ by a factor of two, but the variances are large enough to overlap, indicating that the two sample means are not statistically distinguishable. Basically, they sample averages are not sufficiently different enough to distinguish through the background noise.

I'm also not ready to reject my years of success with this particular salt as I've not had a death not attributed to a mistake in husbandry in over 4 years using this salt, so understandably, I'm not easily convinced that it's certain death, so to speak.

Whatever.

Unless something is detoxifying them, the metals loadings in the salts are sufficient to cause problems with every animal immersed in them. You speak of success, but without a control you really can't tell if these salts are allowing "success" or simply "existence." My guess is that for some species, there are tolerances to heavy metals, for others less so. The former would do all right for a while in these soups, the latter wouldn't. There are very great number of animals that don't survive in our present salt mixes, and I suspect the major reason is heavy metal intolerances. Additionally, we have almost zero success at sexually reproducing animals in our systems, and this is almost certainly due to the metal toxicity. Finally, even among the corals, for example, that we can keep, many clones simply don't thrive.

 

[gregt]

You may say "whatever" to my success, or perhaps lack of failure is a better way of saying it, but as I said, I've yet to lose any species I've tried (and the list is quite long), due to anything other than stupid mistakes in husbandry. Also, I've experienced excellent growth of most species with a few exceptions.

As for the breeding, I can't argue there, but that's a problem I don't want in my display tanks, as it would cause many more problems than it would solve.

That said, I thought I'd made it quite clear I do have a problem with the levels of heavy metals in the mixes in principle. I'm just not convinced based on my experience that it's anything to boycott specific brands on just yet.

 

[rshimek]

Hi Greg,

Well, you might consider that if the levels of the metals seen in these salts were measured in nature, the area would be considered to exceptionally highly polluted; enough so that it would likely qualify as a superfund site here in the states.

The Bioassay formulation has been used by folks for years in the aquaculture industry - it was initially marketed to them because of the mortality they were getting with the standard aquarium salts, so it is a tried and true product.

I obviously am not going to convince you to change your salt mix, but speaking as invertebrate zoologist, it would be far better for your animals to be either in natural sea water or in the closest possible analogue to it rather than in a material that causes such high larval mortality.

 

[jacmyoung]

I too have some problem with how the bioassays were presented and the way the conclusions were made.

Dr. Ron had in the past conducted many scientific studies and I tended to side with his discoveries more so than some other skeptics. But what puzzled me this time is why only four commercially available salts were used, and why the results of the two samples provided by the hobbyists were brushed off some what.

The toxicity studies on the number of the tank samples Dr. Ron did before were limited mainly because of the lab costs involved, but this bioassay study was not very limited by the cost per test. One would have easily obtained many more salt mixes (and there are many many more of them on the market) to be included in the study.

In addition, the freshly mixed salt water did not represent a typical water condition from a typical reef tank. Therefore I thought more weight should have been given to the results of the two tank samples and wished more tank samples of different salt mixes would have been used in the study.

While I don't dispute the notion that high levels of metals are bad for reef inhabitants, making a conclusion that the two brands of salts are superior to the two other brands of salts after this initial round of biosassays seemed premature or at least lacked scientific discipline.

While I certainly am not making any bid of accusation or implication, reading the above article was like reading a study conducted by a manufacture published in a newpaper ad, certainly not typical of Dr. Ron's work that I am familiar with.

 

[gregt]

Well, you might consider that if the levels of the metals seen in these salts were measured in nature, the area would be considered to exceptionally highly polluted; enough so that it would likely qualify as a superfund site here in the states.

True, but you can apply the same statement to the levels of bacteria and organics in our tanks, only more so.

I obviously am not going to convince you to change your salt mix

Not based on this assay alone, no. Because I have to go with what I see rather than what an assay tells me. If you did a test that concluded that I'm a tall, thin, handsome, clever person, that attracts beautiful women in droves, I may be pleased, but it's not going to change reality. In this case, the reality is I'm not seeing any evidence of mortality or poor health due to my choice of salt mix so the test isn't going to change my mind. That doesn't mean that I don't want salt that has has less heavy metals, it simply means I'm not going to react without more information.

Again, I don't think this is a non issue, I do think that it is less of an issue than ammonia, nitrate, shipping, cyanide, nutrition, acclimation, chemical warfare, general levels of organics, soap on your hands, etc, etc, etc . . .

 

[Skipper]

jacmyoung:

In another thread in this forum Dr. Ron responded:

The bottom line on what was tested and what wasn't....

1)I used IO and it is the most popular salt, so I wanted to test it.

2)There have been some questions about Coralife for years, so I wanted to test it.

3)Dennis Tagrin of DT's said that the salt he used in his culturing was low in heavy metals, so I wanted to test it.

4)A hobbyist who heard I was running the tests sent me a free bag of the Bio-Sea, so I tested it.

At this point, I had enough physical space in my office lab for the 88 beakers that testing 4 salts, 2 hobbyists, 2 controls would entail.

And, at this point, I had spent about $1000 in equipment, supplies, urchins, and chemicals for the test.

So I went with that.

Another experimental run would cost about another $500 to $750. I could not and can not afford to do another one, so I didn't test any of the other salts.

That should clear up any confusion you have.

 

[jacmyoung]

jacmyoung:

In another thread in this forum Dr. Ron responded:

That should clear up any confusion you have.

While some of my questions were answered, others did not change. It however raised some new questions. For example the reason why some of the salts were selected in the study seem to indicate a less than impartial position going into the study.

If IO was chosen due to its popularity, the conclusion Dr. Ron made after his bioassays would appear more "grand" than usual, and a grand conslusion requires an equally grand discovery, not just a simple test.

Did anyone bother to ask then why IO was so popular? I am sure with over 60% of reefers using IO (from one of the non-scientific polls taken on another forum), someone must have noticed something bad about IO compared to other salts?

I am not trying to dispute the bioassays Dr. Ron has conducted and the analyses afterwards, only that the study at best calls for more similar studies, not the end of a debate which salt is superior which is not.

 

[jacmyoung]

Let me just add that as critical as I might have sound, I am grateful for Dr. Ron's work in the past and the present. If enough people switch their salt mixes, may be we will get some representive reports from the reefers to support Dr. Ron's theory, or if not we may found something else worth noting as the result of this study.

 

[Martyn]

Hi Ron
An interesting survey something for me to think about.

gregt

just a couple of questions for you.
In Sept 2000 you set up a new tank prior to that you had a tank running for 6 years.

On the 10th of sept you said.
I can't use anything thats ever touched my display tank, as this tanks purpose is to isolate new fish from the display tank until it has proved healthy.
Then I will add it to the tank to see how it does.
I'm trying to prove conclusively that there is something in my display that is killing my fish.

So is the tank you now have the 2 years and 5 months old tank the reef tank and what was killing your fish in the FOWLR at that time?

I am interested as you point out you have been using the salt you use for 4 years with no problems and you say your lack of failure is a better way of saying it, but as I said, I've yet to lose any species.
But you set up a new tank in sept 2000 and you had something killing your fish around that time.

Also I presume the tank you had running for 6 years prior to the new tank at that time was a 55 Gallon FOWLR and the new tank was the reef tank?

And in Feb 2001 you added corals to the FOWLR.
And you have only had a reef tank for 2 years and 5 months from cycling this tank with live rock.
Or am I missing something?
Please correct me if I am wrong.

Regards
Martyn

 

[gregt]

Hi Martyn,

Let me clarify a few things. When I said "species" I was referring to corals, not fish. You are correct in that I did have some trouble keeping newly added fish alive in that tank particular tank, however species commonly known to be highly intolerant to heavy metals were not having problems (such as snails, crabs, etc), so that is not relevant, IMO. Additionally, everything in the tank was moved to the new tank which exception of the substrate.

Sadly, I never was able to explain the fish deaths, however, they stopped after an extended period of the tank having no fish, and I never changed salt mixes. This indicates to me that it was some type of communical disease or paracite. It certainly doesn't seem at all likely it could have been related to heavy metal poisioning.

Dr. Ron, what is your opinion on that matter?

 

[Randy Holmes-Farley]

Greg:


I'm having trouble with your conclusion that heavy metals are responsible for the survival results in your assay.

I think that the metals explanation of the significant differences obtained is a good hypothesis. But there are potentially many other differences between the samples that could also be the "true" explanation. Ammonia, pH, nitrite, nitrate, sulfate, organics, and a host of other chemical atttributes remain possibilities.

 

[rshimek]

Hi Randy,

So... set up and run the tests.

At the present time, as I indicated earlier, we don't know what is causing the differences. Heavy metals concentrations as high as are found in the mixes are considered to be problems in marine systems whereever they are found. I think that they are most reasonable potential cause of the results I obtained, but there certainly could be other causes.

The field is open for other folks to do some controlled tests. I welcome any additional results.

 

[rshimek]

Originally posted by gregt

Hi Greg,

. It certainly doesn't seem at all likely it could have been related to heavy metal poisioning.

Actually, it might be. Randy and Habib have postulated that heavy metal toxicity in tanks is reduced by bacterially generated materials or other materials such as humic acids. Once a tank is set up for any length of time, it is effectively a bacterial culture vessel and these organisms cover every surface in it. That some tanks can start with a salt that kills larva and still support life well, is evidenced by the one hobbyist in the study whose water did pretty well. The "freshly mixed" salt water would be "nasty," the older water would be less so, and may well be below the level of acute problems.

 

[palkin-kopalkin]

This is for Greg,
Maybe I missed it but what type of salt do you use?

 

[gregt]

Dr. Ron,

Did you see that the problem was with newly added fish? They were dying in a one to two week period of adding them to the tank. After leaving the tank empty for three months (I honestly don't remember whether water changes were done during or immediately after that period. I probably have logs with that information somewhere . . .). New fish added after the three month period were fine.

Also, if it was heavy metal poisioning, wouldn't the snails, crabs and other inverts die long before fish?

palkin-kopalkin, I didn't say.

 

[barry769]

Actually, it might be. Randy and Habib have postulated that heavy metal toxicity in tanks is reduced by bacterially generated materials or other materials such as humic acids. Once a tank is set up for any length of time, it is effectively a bacterial culture vessel and these organisms cover every surface in it. That some tanks can start with a salt that kills larva and still support life well, is evidenced by the one hobbyist in the study whose water did pretty well. The "freshly mixed" salt water would be "nasty," the older water would be less so, and may well be below the level of acute problems.

I am wondering if this might be related at all to the reason why many of the less hardy additions to our tank, such as corals anemones and some fish, must wait 6 months before the tank "matures", long after the initial cycling of the tank has finished.

-Scott