New Salt Mix Data?

[Habib]

Ok, I'll spill it: there was no correlaion between what metals were found, and the urchin larvae survival. Further, while IO was among the best salts, Reef Crystals was among the worst, just for those who are naturally cynical.

One of the questions I asjed is what the difference is between Reef Crystals and IO since both are made by the same manufacturer.

IIRC Tim said Reef Crystals contains more calcium, trace elements and contains some vitamins.

The additional amount of the trace element enriched Reef crystals is a few ppb's.

Makes one wonder why the results were so different.

[Randy Holmes-Farley]

[I was at that time too busy thinking about some of his results.

Yes, you were too busy noticing that one of his criticisms of Ron's study (too poor of survival in the NSW "control" ) also applied in Tim's study.

[WaterKeeper]

Originally posted by Habib
There will be a filter but the sample is acidified. If that happens before it is filtered then metal precipitates will dissolve and will be measured.

This is less likely if the precipitate is large enough to be filtered and the filtrate is acidified.

I buy that too Habib. Proper technique would be to filter the sample immediately upon collection than acidify the filtrate. I need to look back and see how the samples were handled in the Tank study. I don't recall if filtration was part of that protocol.

[photobarry]

Originally posted by WaterKeeper
Proper technique would be to filter the sample immediately upon collection than acidify the filtrate. I need to look back and see how the samples were handled in the Tank study. I don't recall if filtration was part of that protocol.

I still don't understand why you don't think particulate matter in the water should be part of the analysis.

For example: I use sand filtered NSW that I get here at work. If I wanted to analyse it for trace metals I would not 0.2 micron filter it right after drawing it from the tap. That might remove a bunch of material that would normally find its way into my tank and therefore not be representative of the water I use for water changes.

[jfinch]

IIRC Tim said Reef Crystals contains more calcium, trace elements and contains some vitamins.

When he presented this data at our club meeting he told us that EDTA is also added to reef crystals.

[Randy Holmes-Farley]

Makes one wonder why the results were so different.

I think he started to say at one point that any or all of the actual ingredients may be different, even if the end results are only different in the way that you pointed out. He said clearly that he did not want to say anything about the manufaturing process.

[Habib]

Thanks.

He said clearly that he did not want to say anything about the manufaturing process.

I think it is best if I / we would act like he is a third party having done the tests knowing nothing about the manufacturering processes.

[jfinch]

What do you assume/know about the manufacturing process that might explain the results?

I personally wondered about the EDTA. If those trace elements are really as low as his analysis indicated, maybe some biologically important element was not available because it was chelated with the the EDTA?

[Randy Holmes-Farley]

The question related to the difference between IO (among the best)and Reef Crystals (among the worst).

He told us what the intended chemical differences are, but one might infer that NaCl added to IO and RC are the same. They may not be. So the intended differences between the mixes may not be the only actual differences. Consequently, to conclude that the vitamins/calcium/etc. are the difference may be in error.

FWIW, I asked him directly if anything in IO was targetted to be different than NSW, and he said the only intended difference was bicarbonate (alkalinity).

[jfinch]

He also said IO (and as far as he knew, all other salt manufactures) did not purposefully add any trace elements. What showed up in his scans was what entered the mix via contaminates in the other constituent salts.

...one might infer that NaCl added to IO and RC are the same. They may not be.

I see. But is that very likely? I would think Marineland would just buy, say NaCl from Cargill (or whoever), in bulk and use it in all salt mixes. That way you only have to inventory one "brand" of NaCl. i.e. if it's good enough for IO it's good enough for RC. The amounts of each constituent salt would have to be adjusted for the additional CaCl2 in RC which might account for the minor differences in trace elements.

[Habib]

I suspect the accuracy of the copper (and perhaps a few more metals).

There are some strange and funny things which don't make sense and I'm checking them.

[Greg Hiller]

Photobarry,

>In their defense, I think they were trying to simulate how a hobbyist might collect NSW. I don't know of any hobbyists that will micron filter their SW. So, all that plankton will likely end up in the tank.<

I see your point, but I think one of the reasons for including the NSW was to show that the test method was yielding the result that would be expected for NSW. I would expect that trace metals in NSW would very dramtically from place to place depending upon the plankton in it (this is assuming you burned up the plankton in the analysis), whereas, NSW with the plankton removed would probably have less variation by geographical collection site.

If you are using NSW as a comparison, or benchmark to compare the artificial sea salts to then you would not want a sample of NSW that was artifically high in plankton, and therefore trace metals.

It might have been best to run BOTH, filtered and unfiltered NSW and then you would see the difference the plankton might make.

[WaterKeeper]

This is an apples and oranges thing. If you mix pristine salt mix you would want of compare it to pristine seawater, that is, without plankton or any stirred up sediment in it. On the other hand if you are analyzing tank water then you might want to use a unfiltered seawater sample for comparison. If we want soluble metals then we need to filter the sample. If we want total metals then we want an unfiltered sample and ideally acid digested. So much here depends upon the analytical technique used. If we use ICP or graphite furnace AA, it really doesn't matter if the sample is acid digested as the method will vaporize any solids in the sample and they will show up in the overall analysis. Use a colorimetric or flame AA technique and particulates will not show up, well they may but as an interference rather than a true metallic value. No matter what method is used the sample preparation should be the same for all samples, regardless of origin. and the preparation methods used described in the article.

Jon,

Using ICP chelated metals will show up in the readout. The same is true of using AA, either electrothermic or plain flame. It would impact colorimetric methods.

[tonylamas]

Tom,

Pristine water vs pristine water in the comparison makes sense for a lot of scientific methodology reasons, but what if the goal was to see what is in the water we put in our tanks? I think both filtered and unfiltered should have been run. I don't know how many people filter NSW when they use it, but it would still be an important number. If you don't filter, it still goes in your tank. Besides, that would be an interesting comparison in itself that may have implications on metal export fro the water column.

[WaterKeeper]

That was my point. Freshly made ASW should be compared to filtered NSW as the ASW doesn't have any organisms in it. On the other hand, when you measure your tank water it would be wise to use unfiltered NSW and tank water for the comparison as you are now measuring "used", for a lack of a better term, ASW populated with microorganisms in your tank. In the first case we are measuring dissolved metals and in the second total metals.

No matter how you do it all samples should receive exactly the same treatment and that sample preparation should be mentioned in the article.

[tonylamas]

Gotcha.

My personality type is "information gatherer." So strongly that I'm dysfunctional sometimes. I always want all the variables nailed down.

[photobarry]

Originally posted by Greg Hiller
It might have been best to run BOTH, filtered and unfiltered NSW and then you would see the difference the plankton might make.

I agree.

[jfinch]

My comment regarding EDTA in RC perhaps causing a problem was more to do with the urchin test, not the ICP. Sorry for the confusion.

[Ninong]

Originally posted by jfinch
IIRC Tim said Reef Crystals contains more calcium, trace elements and contains some vitamins.

When he presented this data at our club meeting he told us that EDTA is also added to reef crystals.

That's interesting. I thought he had previously told someone that Reef Crystals contained a chelating agent other than EDTA??? Maybe that previous conversation was not reported accurately. The person who reported that previous conversation claimed that Tim refused to identify the chelator in Reef Crystals because it was "proprietary information."

Or maybe the reluctance to admit that it is actually EDTA (if in fact it is) can be traced to their former ad copy for I.O. which stated that "it does not contain harmful EDTA, never has, never will." Of course, we all know that Instant Ocean did once contain EDTA because Aquarium Systems published their own assay stating 0.06 ppm EDTA in their own little handbook, but that was about 20 years ago. And one of the other brands of salt mix that they manufacture under a German label used to advertize "no harmful EDTA." Looks like those phrases have been removed recently from Instant Ocean ads and Aqua-Medic ads.

[Ninong]

I can certainly understand why Tim would not want to make comparisons against any of the published NSW values. Why would he want to make artificial salt mixes look bad? I think he has a valid point about using NSW that is available to most hobbyists and I am glad that he included Catalina water. I'm rather surprised by the results considering the claims made by Catalina but that's another question. I wish he had included some NSW samples from the Seattle Aquarium and from Scripps, since those are two popular sources of NSW for hobbyists. I'm sure there are commercial sources for NSW in Florida, too, but I'm not familiar with those. Not many hobbyists collect their own NSW off Malibu.

Anyway, his articles are bound to be interesting to say the least. We will all have to watch the AquaCraft website for Michael Del Prete's sure to be colorful rebuttal.

[cephalopoder]

When I asked the Aquarium Systems people at MACNA about the metal detox component it Reef Crystals they told me it was EDTA and had always been in Reef Crystals and only recently anounced on the buckets that Reef Crystals had a metal detox (EDTA) in it . The reason being I was told that they figured since it always had a metal detox component in the salt they might as well advertise it.
I am curious how EDTA is or can be harmful in the aquarium? From a recent discussion with a friend of mine that is a commercial shrimp farmer, I was told P.vannamei shrimp farmers add EDTA to the tanks they rear the nauplii in.
chris

[WaterKeeper]

I think we need to get Randy to do his next RC article on chelated metals vs. the Plain Jane metals we all have come to know and love.

Really, there is little or no data on whether metals sequester by an organic chelant, like EDTA, are any less toxic than an inorganic compound. There are several copper based ich medication that use EDTA in their formulation and appear to cure ich just as well as copper sulfate. There is, however, little published data on the difference in toxicity between the chelated version and the inorganic form.

[Randy Holmes-Farley]

EDTA iron is apparently not biologically available until it is broken apart by UV. There is an extensive discussion in "Captive Seawater Fishes" by Spotte.

[sterlruth]

So for someone like myself who has not idea about Chemistry...

...should I use Tropic Marin or Crystal Sea Marinemix?

These are the two available to me so...

Thanks

Steve

[sterlruth]

Any thoughts about my post? Tropic v. Marine?