Comparison of two different salt mix studies:

[Ninong]

I decided to compare some of the trace elements that were tested in Dr. Tim Hovanec's study (Advanced Aquarist, Vol. 3, Issue 9, Sept. 2004) against the results for the same salt brands in Matt Marulla's study (Advanced Aquarist, November 2005).

Starting in alphabetical order, Aluminum was tested in both studies.

Tim detected no aluminum in Oceanic salt (actually <8 ppb since the detection limit was 8 ppb). Matt measured 69 ppb Al in Oceanic salt.

Tim detected no aluminum in Bio Sea Marinemix (<8 ppb) whereas Matt measured 52 ppb Al in the same salt.

Tim detected no aluminum in Instant Ocean (<8 ppb) but Matt found 33 ppb Al in Instant Ocean.

Tim detected 10 ppb Al in Crystal Sea Bioassay but Matt measured 32 ppb Al in that salt.

Chromium:

Tim reported 0.29 ppb Cr in Instant Ocean but Matt found 4 ppb Cr in that salt.

Tim detected 0.65 ppb Cr in Oceanic vs. the 9 ppb that Matt found.

Tim reports 1.0 ppb Cr in CS Bio but Matt found 9 ppb Cr in CS Bioassay salt.

Copper:

Tim was unable to detect Copper in any of the salt mixes he tested (detection limit 3 ppb). Matt reported higher than 3 ppb Cu in all of the salts he tested: 8 ppb in Oceanic, 7 ppb in Bio Sea Marinemix, 5 ppb in Instant Ocean and 6 ppb in CS Bioassay.

Zinc:

Tim measured no zinc in Oceanic (detection limit 2 ppb) but Matt claims that Oceanic has 79 ppb Zn.

Tim found no zinc in Instant Ocean, Matt found 4 ppb Zn in I.O.

Tim found no zinc in CS Bioassay formula salt mix and, believe it or not, Matt agrees with that result. He found no zinc in CS Bioassay.


Interesting test results, I suppose.

What do you think?

 

[fungia]

maybe it is a quality control problem with salts, maybe it is the testing procedure. all four salt tests i have read show different results so i dont know what to agree with.

 

[dave_atl]

it all tastes the same to me

 

[liquid]

Could be procedure, it could be the equipment used, it could be process variation. No way to really be sure.

Shane

 

[melas]

surely some of the discrepancy is due to differing testing equipment and environments but i do believe that much of the variation is due to the simple fact that the salt is mined out of the earth (from the beds of ancient oceans) and thus subject to regional and local variation in composition.

 

[Anonymous]

Interesting.

 

[Anonymous]

I don't know what to think of this. I can understand some slight variations based on different testing environments and procedures, but some of these results are night and day. Interesting indeed.

 

[liquid]

simple fact that the salt is mined out of the earth (from the beds of ancient oceans) and thus subject to regional and local variation in composition.

I am under the impression that our aquarium salts are made by blending raw materials together and not mining salt from a mine.

Shane

 

[Anonymous]

I'd figure that most of those raw materials come from evaporate deposits which are mined. I may be wrong though.

 

[melas]

mining or evaporative removal from sea water/saline lakes . . . that's the only way salt is really mass-produced. . . either way it comes from the ocean, "trace" elements included. as far as the calcium and carbonates. . . those are most likely added via raw forms produced by other processes. there is a guy near me that is making sea salt using halite (rock salt), baking soda, de-icer and pickling lime (his tanks look absolutely awesome - some of the best i've seen privately). i've already started doing some of my own work to figure out an easy to follow "recipie" for a DIY salt mix, the results of which I intend to freely share (unlike this guy who is extremely protective of his "secret"). My preliminary work looks promising. I have found everything i need. i'm currently working on ratios.

 

[Anonymous]

Heres the response from the church of Dr. Ron:

http://www.reefcentral.com/forums/showthread.php?s=cb503747a66b3b8744f6dc3548d3cb61&threadid=710422


:roll:

 

[melas]

an interesting post. . . another point not mentioned here nor there could be the fact they are only using small samples from a large container. If y amount of chemical x is added to a 200 gallon bucket of salt and mixed with q amount of chemical z who's to say that when you take a few cups from the top of the bucket that you will be getting a proper ratio of chemical x and z? If the particulate size of these two chemicals vary at all, some settlement would occur with the larger particles "rising" to the top of the mix. we also have to assume that the mix was completely homogenous to begin with. this is why i do not buy more salt than i can mix at one time. i have 25 gallon trash cans that i use to make 25 gallons of saltwater. that way i know that (assuming the proper ratio was put into the bag in the first place) i am getting a mix with the proper ratios.

 

[Ninong]

I wonder why Matt's test results seem to be higher across the board when compared to Tim's test results? Both were measured with ICP-MS.

It seems odd that one test would measure 79 ppb of something (zinc in Oceanic) in a salt that the other test measured none, unless this is a reflection of the margin of error with this procedure when measuring in the parts per billion range??? In which case, it seems to indicate that the lab used for Matt's tests was consistently high compared to Tim's tests and this at least shows consistency???

I didn't compare all of the results, just a few that I selected after three minutes of exhaustive research. However, upon further examination I couldn't help but notice that Matt's lab found 180 ppm Mn in Oceanic. Wow! That's a lot of Manganese! I wonder if that's an error that somehow eluded the peer review?

 

[ReeferAl]

None of the salts is "best" in regard to every metal, which makes it hard to compare. Some metals may be much more toxic than others so a salt that is high in a more toxic component may be worse than a salt that is high in 2 or 3 less toxic metals. I did a little tally myself, just for a rough comparison. I added up how many times each salt was "bad". This is not particularly scientific as my criteria are somewhat arbitrary. A salt was counted if it was worse than NSW (for those where some were worse but others near to NSW), where it was worse than the average of the salts (for metals where all were higher than NSW), or where 1 or 2 stood out as considerably higher than the others. I didn't count boron or bromine as they shouldn't be toxic. For strontium I only counted those significantly above NSW levels as this could be toxic at higher levels although possibly necessary at lower levels. Here are my totals:

Matt's test:
* Aqua Medic 9
* Oceanic 9
* Omega Sea 7
* Bio-sea Marinemix 7
* Crystal Sea Marine Mix 7
* Tropic Marin 5
* Instant Ocean 4
* Kent Marine 5
* Crystal Sea Bioassay 8

Tim's test:
* Oceanic 2
* Red Sea 2
* Bio-sea Marinemix 7
* Crystal Sea Marine Mix 6
* Tropic Marin 4
* Instant Ocean 1
* Coral Life 3
* Reef Crystals 2


From Matt's study, Instant Ocean, Kent Marine and Tropic Marin all look pretty good. Rather high metal content is seen in Oceanic and Aqua Medic, with Crystal Sea Bioassay close behind. In Tim's study Instant Ocean, Reef Crystals, Red Sea and Oceanic look best and Bio Sea Marine Mix and Crystal Sea Marine Mix look worst. The studies tested different salts so not all can be compared.
The closest agreement between the 2 studies is that Instant Ocean came out looking good. Bio Sea and Crystal Sea Marine Mix don't look very good in either study. Tropic Marin looks fairly good in both. Oceanic salt stands out as the biggest disagreement between the 2.

I think I'll stick with IO.
Allen

 

[MattM]

an interesting post. . . another point not mentioned here nor there could be the fact they are only using small samples from a large container. ... If the particulate size of these two chemicals vary at all, some settlement would occur with the larger particles "rising" to the top of the mix. we also have to assume that the mix was completely homogenous to begin with.

Please re-read the section on procedure. We did take this into account.

- Mathew Marulla

 

[MattM]

From Matt's study, Instant Ocean, Kent Marine and Tropic Marin all look pretty good.... I think I'll stick with IO.

I think you will be intruiged when you read part two next month!

- Mathew Marulla

 

[MattM]

I wonder why Matt's test results seem to be higher across the board when compared to Tim's test results? Both were measured with ICP-MS.

Several tests were moved to the end of the article because there was no significant difference between the salts. Those tests won't show up until part two next month. In those tests are things like Calcium and Magnesium which all tested exactly at the levels you would expect. So it may be premature to assume our results were "higher across the board."

On some other boards we have been taken to task for not providing more technical details on the testing, despite the fact that we provided the same level of technical detail as Hovanec, Shimek, or Atkinson and Bingman.

In any case, the analysis was done by Northern Analytical Laboratories in Merrimack, NH. They specialize in trace element analysis down to the part-per-trillion range. This is the same lab that we used for Combi-San and Miricale Mud. FYI, their results in those two tests were highly accurate and never questioned. We have no reason to expect any different in this test. The instrument used was a VG Elemental PlasmaQuad PQ3 ICPMS.

Finally, some of the issues brought up here may be addressed in part two. While I am fine with answering questions, I don't want to prematurely give away anything that appears in that article.

- Mathew Marulla

 

[Ninong]

I didn't compare all of the results, just a few that I selected after three minutes of exhaustive research. However, upon further examination I couldn't help but notice that Matt's lab found 180 ppm Mn in Oceanic. Wow! That's a lot of Manganese! I wonder if that's an error that somehow eluded the peer review?

While I am fine with answering questions, I don't want to prematurely give away anything that appears in that article.

- Mathew Marulla

How about your manganese measurement in Oceanic salt? Don't you think 180 ppm Mn is rather high? Even calcium is only 411 ppm in NSW. NSW concentration of Mn is usually given as 0.0004 ppm.

P.S. -- I was using a 1968 reference for Mn at 0.0004 ppm. Tim Hovanec used a 1998 reference in his article published in the Sept. 2004 Advanced Aquarist and he gives NSW concentration of Mn as 0.000027 ppm. Either way, your test results are incredible to say the least.

Also, I was surprised to see that you found 2 ppm Lead in CS Bioassay formula salt mix vs. 2 ppb Lead in the same salt according to Tim's testing. Your figure, assuming it is correct, is exactly 1,000,000 times NSW concentration of Pb according to Tim's reference of 0.000002 ppm Pb in NSW.

Obviously nothing could survive in saltwater that contained 180 ppm Mn so there's no need to research the toxicity threshold for that one but it may be interesting to research toxicity for 2 ppm Pb to see what that would kill, if anything. I wonder if that much lead would be toxic to anything? I know copper in the low ppb range is toxic to some inverts. Maybe I could ask the guys at the EPA lab in Baton Rouge? They use CS Bioassay salt for all their bioassay testing.

Was your article peer reviewed?

 

[Ninong]

Matt,

Mn at 16.0 ppm and Pb at 2.45 ppm is toxic to this oyster: http://www.springerlink.com/(4a0gb455tggnuu55o5g5piu0)/app/home/contribution.asp?referrer=parent&backto=issue,2,9;journal,396,466;linkingpublicationresults,1:400441,1

And according to the USGS, lead at concentrations of 1 - 5.1 ppm is toxic to many forms of marine life: http://www.pwrc.usgs.gov/infobase/eisle ... 4_Lead.pdf

To put it plainly, you couldn't have found the values of manganese and lead that you reported or nothing would be alive in the tanks using those salts.

Manganese at more than 6 million times NSW and lead at 1 million times NSW is ridiculous.

 

[Habib (Salifert)]

When I saw the results a few days ago, in a quick glance, the first thoughts were that the bromide values might be wrong and that the manganese values can't be that high... perhaps ppm should read ppb in this case.


I don't see a reason why using a different batch of salt, different technique, done by different operators etc should not produce different results.


However, it is a pity that not NSW as a sample was included as was suggested to Matt in te very long thread.