AWT salt test results

[cee]

Aquarium Water Testing did an analysis of popular synthetic salt mixes and the results can be found here:
http://reefsaltanalysis.googlepages.com/AWT_Salt_Analysis_0208.pdf
I won't discuss the implications here as I've not had much time to study it, but it might be a good topic (albeit boring for some) for a future meeting.

Dave

 

[ct_vol]

I look forward to reading it... I hope its not as controversial as the last SW study that was exhibited at MACNA last year or the year before...

 

[digidana]

wow, very interesting. its amazing to see the difference just within the same brands.

 

[acrodave]

wow i use tmpr and have now for over a year . and i cant believe there is that much ammonia that is in it .. but at lest it stayed constant on all the charts and not jumping around

 

[fishdoc11]

Nice of them to do but there still seem to be some some major flaws experimentally speaking. Mainly that they didn't normalize SG. Sample size is also too small and there are too few samples.
Here is an interesting discussion on it:
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1317416&perpage=25&pagenumber=1
An even more interesting discussion:
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1317727
FWIW, Chris

 

[cee]

I agree about normalization of the salinity, but the data is there to extrapolate to any S.G. you want and predict the levels. It was never susposed to be a scientific study, and I think it says so in the abstract, so sample size is based on what they could reasonably do. Also, I suspect the ReefCrystal results are off because that is when the bad batches were floating around. I've not read the links, this is my own opinion.

 

[fishdoc11]

You might want to click on the second thread Dave....some pretty good points are made in it about the validity of the #'s

 

[cee]

Thanks, Chris, I did just that. I agree that "scientifically speaking" there is some missing information about how the tests were performed, controls used, etc. I never use these studies to predict absolute performance but do find them useful for relative comparisons. One has to assume that they are consistent in how they test each batch.

 

[KafudaFish]

I quickly looked through the report the other day and have not been back since but the data are not really showing that much variation between brands rather between the two samples of each brand. If you look at the bars then it really looks like there is large variation in the values but when you look at the scale per test, then most brands fell into very similar values.
Again I did not look things over too closely but I don't understand why they did not normalize the samples before testing. Who is going to test the calcium level of brackish water for a reef tank?

 

[ct_vol]

What salt are you using these days Dave??? I know you had talked about going over to RS Coral Pro about a year ago...


I go back and forth between RSCP and Reef Crystals...

 

[fishdoc11]

<a href=showthread.php?s=&postid=11842677#post11842677 target=_blank>Originally posted</a> by KafudaFish
I quickly looked through the report the other day and have not been back since but the data are not really showing that much variation between brands rather between the two samples of each brand.

That's basically what I saw. Can't get onto the site at the moment but it seemed like large variations between only 2 samples of each salt and those were significantly different. It's just hard to have any confidence in data with only 2 data points that are so far apart. They need to do the test with larger amounts of better mixed product with many more samples analized IMO.....correcting for salinity/SG would be great as it's inconvienant to extrapolate the data....that's the job of the author......as is the conclusion.
While I agree this is a decent attempt at creating some sort of info what scares me about reports like this is that the general public has no clue how to interprit well designed and poorly designed studies so they are going to make the conclusion that this is good info and IMO it's majorly flawed.
Chris

 

[KafudaFish]

Statisitics never lie but the way the information is presented can paint any picture a researcher wants. How many times does someone throw out a datum point because it must be an error etc.?
You can watch a commerical about a fat pill and they say that they used a double blind random study so it must be good. Then in fine print at the bottom of the screen with 2 point font they will say the placebo group lost 3 pounds while the test group lost 5 pounds over the 12 weeks. They also followed a diet and exercise program as well. If you call now you can get a 2 month supply for only $60. When you run out of pills half way through don't worry because you have already signed up for automatic delivery for the regular price of $150/month. Please allow 3 months to cancel your automatic delivery and you will be charged regular price each month.

 

[fishdoc11]

But your not supposed to throw out ANY data points.......one just explains them in the conclusion.....ie 13 dogs were removed from the study for humane reasons. FWIW I don't think the AWT guys have any hidden agendas and I think their intention was good.
Chris

 

[cee]

The large variations only appear to occur on the measurements of trace elements and are likely due to errors encountered in the test procedures which are to be expected when you're trying to measure less than one part per million. That doesn't surprise me nor does it indicate a flaw IMO. Other variations in the major constitutents in salt water are likely due to settling during shipping, and thus, I believe, represent reasonably well what the average hobbyist should expect in the way of variation when mixing up the salt. After all, nobody I know mixes the bucket of salt prior to use, it is just too heavy and burdensome. Also, if you read the link #2, it seems to indicate, based on communication with the study author, that the chemical analysis was all performed with 35 ppt mixed samples. Obviously, this should have been made clear in the report. Finally, this is not a scientific paper and shouldn't be compared to one.

Randy, I tried RSCP once and didn't like it. Everytime I mixed it, there were solid particulates in it which I didn't know what they were. I mix IO and Oceanic, giving me a near NSW mix. I then add RC (it was cheap) and SeaChem to boost the boron alkalinity. So, by mixing 4 products, I don't worry too much about the bad attributes in one salt vs. the good in another because it all washes out in the end.

Dave

 

[RevHtree]

Great Link Dave!

 

[KafudaFish]

Chris I agree that nothing should be thrown out but sometimes it is sweeped under the rug.

Dave,
I have wondered if anyone ever mixed different salt mixes into ONE. How long have you done this?

 

[cee]

About 2 years, and every salt mix has had some kind of problem during that period.

 

[fishdoc11]

<a href=showthread.php?s=&postid=11844790#post11844790 target=_blank>Originally posted</a> by cee
Finally, this is not a scientific paper and shouldn't be compared to one.

I partly agree but my concern is it will be taken as one by the general reefing public. Of course people are going to see what they want to so I don't know why I'm worried about it.
It's just annoying to me that so much "hobbyist science" is taken as fact at face value.