Salt Analysis Study Results

Sorry if I seem ungrateful, but I am tempered with the knowledge that AWT did not do this exactly for "free", this PDF is as much an advertisement as it is a report.

I just have reservations regarding AWT. Everyone seems to see the word "lab" and label them infallible. I don't know, I find their to be many questions brought up previously, and even in this thread regarding their methods. Sometimes their numbers don't even make sense, and they can 't explain why.

What do we really know about AWT other than it is someone who invested in a digital titrator and photometer from Hach? They even state they are still calling Hach customer service to figure out their methods... Randy even points out basic tests they could have run to verify their data.. These are common tests in a "lab", especially if you have odd data...

Anyway, sorry to be so negative..
 
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I think if anything this just further reinforces the total randomness of our hobbiest aquarium salt. If we all saved our numbers through the years, and than consider the various reports results through the various years, we can come to the conclusion that in general salt mixes are a pure crap shoot. Whatever brand of salt you buy or are loyal to, is going to have good and bad bags pretty consistently, in fact their inconsistentcy is their biggest consisistency!

Someday, someday there will be a consistent salt :)

Heck I've even personally in the last 5 years landed a bag of the 600 calc 3 dkh Kent, and my current 2 buckets of crap 300calc 1000mg 12dkh Reef Crystals, oh and bad bag of the 800mg TM Pro to! wooo.


PW
 
<a href=showthread.php?s=&postid=11821819#post11821819 target=_blank>Originally posted</a> by melev
After reading all the work they put into this study, how can anyone not be impressed with how they went about doing this series of tests? New RO/DI system for the test, acid washed barrels, some mixing of salt (who really stirs their bucket of salt before making ASW?), and all the double testing of these many salts, each unlabeled to avoid skewing the results... I think they did a very nice job with what they tried to accomplish.

I would like to know how to convert some of the measurements from mg/l to ppm, such as the Bromine number. They pointed out the number we would aim for, but the results are in a different measurement.

Thank you AWT for doing this. It is very interesting.
Click to expand...

Melev,

1 mg/l = 1 ppm. Easiest conversion there is.
 
basically we learned to mix dry salt if it comes in a bucket or box, and if you sell salt start working on packaging. How about 4-6 small bags in the bucket? i think i got IO like this once before.
 
<a href=showthread.php?s=&postid=11824249#post11824249 target=_blank>Originally posted</a> by emoore
Melev,

1 mg/l = 1 ppm. Easiest conversion there is.
Click to expand...

Thanks for that.

I see the comment "n=" quite often. Why "n"? What is its signficant? Is that just a variable, and "n" is the favorite letter?
 
n=number of things in the sample population. Stats lingo. In this case 2 samples of each "population" (aka salt mix)
 
Thank you for that. Certain things really don't matter to me, but I've seen it come up often enough lately that I figured maybe I needed to know it.

n=+1

:lol:
 
I really appreciate the hard work that went into this study. Considering that this study (apparently) was funded out of pocket from the researchers, it was a very generous endeavor.

However, I have one major criticism; the sample size. You can't really know how many samples should be selected without a good pilot study (say measuring many samples of one particular brand of salt). But, in most every case in life, 2 samples is never enough to paint an adequate picture of a population. In just the two samples selected for most of these brands, you can see some rather large variance in different tests. This is a good indicator that much more testing is needed. Using more samples of each salt would not only provide a much better approximation of their true average values for these tests, but it would also give us an understanding of how much variance is involved with the different brands. Personally, I would be more interested in the variance than the mean for these tests. You can find ways to correct for things that are consistently bad more easily than correcting for things that are randomly occasionally bad.

I realize it would be time consuming and expensive to increase the sample sizes for these tests. If it were offered, I would definitely donate a few bucks to see a more intense version of this study.
 
Dr.

First, thanks for taking the time and pushing the issue of getting this done. And I thank you still again . :thumbsup:

As we all know on any salt study there will always be issues on how it was done or should of been done but at least they took the time and spent the money to give us something and I do appreciate AWT for doing this salt test study for us.


My hope was my own posted request long ago on can they do Bromide. I found this part of the test very disappointing as Randy did. First, there have been many salt assays in the last 20 years or so and all show Bromide at least in the 10's of ppm. For all practical purposes they show almost nil which is just not so. I'm beginning to wonder if they did not understand the question " can they test for " Bromide" and instead tested for Bromine. One could maybe suspect Bromine levels that low or a least maybe some Bromine test noise. One needs to look at for example the Bromide, if that is what it is at almost zero for all particle purposes and compare that with the Inland Study which ahs Bromide in the 100's of ppm. It appears that they both have some serious testing issues with Bromide. About the only real means is ICP or some of the old seawater methods like H2SO4 acidification where the Bromide is then determined by volumetric means.

As far as those asking about bringing the mixes to 35 ppt ? It is quite common to measure 35 grams of salt mix with 96.5 grams of RO/DI water for the soul purpose of seeing how much moisture ( H20) there is in the mix. If a salt was weighed to 35 grams and the Salinity ended @ 31 ppt then 4 ppt is water or in other words the mix is 11. 5 % water. Usually once this is done then the salt is normalized to an actual 35 ppt and then the ions are tested for.

In regards to the way the graphs were done I have no real issue but they should have had a bar graph with NSW Copenhagen stds, so some do not have to go look up ions they are not familiar with and what they should be in NSW, i.e., Ca++ = 10.27 mmol/kg = 412 ppm, Mg ++ = 52.7 mmol/kg = 1280 ppm, Mo = 100 nmol/kg = .0095 ppm ,etc.. All studies I have seen have had a bar on NSW for comparison.


Billybeau

Thanks old bud for doing all the conversion for everybody to 35 ppt. That means I won't need new batteries :lol:
 
Hey Boom. Actually, I kinda liked the fact that they measured out exactly the same grams of each mix.

This gives everyone an idea of how much salt the different brands need to make 35 ppt.

If one were to actually crunch the numbers, they would see that some salts, although more expensive initially, actually produce more gallons of salt at 35 ppt.

This could be a big deal for those with bigger tanks.

After all, calcium and magnesium levels are the biggest things we're concerned about, right.

All these other numbers are so minor, that most reefers will never see a difference in their tanks.

Until we hear of a commercial salt mix actually killing tanks, I suspect all the rest of this stuff is worry for nothing. :)

BTW, I have several comments about this study that I will reserve for another day.

That said, I take my hat off to AWT for stepping up to the plate. This was a very bold (and dangerous) move on their part.
 
is the PO4 reading in the IO large enough for concern? I was having hair algae problems before i had to break down my tank, even though I was running a PO4 reactor and skimming heavily.. I'm wondering if this was the case. I never even thought to check my newly mixed salt water for PO4.. I might have to try the Coralife brand next time.. it looks like it had pretty positive results. Thanks for the testing!
 
<a href=showthread.php?s=&postid=11827041#post11827041 target=_blank>Originally posted</a> by Billybeau1
Hey Boom. Actually, I kinda liked the fact that they measured out exactly the same grams of each mix.

This gives everyone an idea of how much salt the different brands need to make 35 ppt.

If one were to actually crunch the numbers, they would see that some salts, although more expensive initially, actually produce more gallons of salt at 35 ppt.
Click to expand...

I understand this, and I do like that they did this test, but before measuring all the other values they should have brought all samples to 35ppt. We hobbyists don't weigh our salt and add it to a given volume of water and let our tanks run at whatever salinity that comes up with. We add however much salt it takes to run at a given salinity. So while this one test is important as you said before, it kind of skewed the results for everything else.

Not trying to be negative, but this is an huge glaring issue to me. With all the other measures they took to replicate hobbyists and ensure accuracy, wouldnt mixing it to the same salinity be the most obvious action?
 
It seems to me all of the data is available to normalize all of their results to 35ppt -- the math would be very simple. I'm not a chemist, so I don't know if all of their results (phosphates, nitrates, etc..) would scale linearly but I would imagine they would. Anyone?
 
"is the PO4 reading in the IO large enough for concern? I was having hair algae problems before i had to break down my tank, even though I was running a PO4 reactor and skimming heavily.. I'm wondering if this was the case. I never even thought to check my newly mixed salt water for PO4.. I might have to try the Coralife brand next time.. it looks like it had pretty positive results. Thanks for the testing!"

Same here, I have been battling HA since switching to TM pro last summer, never thought to check the new salt mix. Maybe time for a switch.
 
<a href=showthread.php?s=&postid=11827445#post11827445 target=_blank>Originally posted</a> by LobsterOfJustice
I understand this, and I do like that they did this test, but before measuring all the other values they should have brought all samples to 35ppt. We hobbyists don't weigh our salt and add it to a given volume of water and let our tanks run at whatever salinity that comes up with. We add however much salt it takes to run at a given salinity. So while this one test is important as you said before, it kind of skewed the results for everything else.

Not trying to be negative, but this is an huge glaring issue to me. With all the other measures they took to replicate hobbyists and ensure accuracy, wouldnt mixing it to the same salinity be the most obvious action?
Click to expand...

I totally agree, from a hobbyist/end-user POV. None the less, This survey is awsome as it puts hard numbers on the table.

I vote that as a logical next step we select 2-3 of the most promising salts (like Coralife) and run a much larger sample through AWT. Perhaps 20 or so bags of each selected salt can be purchased from all around the US and sent to AWT. Maybe if we paid for the salt/shipping/testing they would compile the results for us?

Just an idea,

James
 
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