Salt Tests

[Dorkhedeos]

Do any of you have that website that had the salt brand comparisons and tests of their composition? I vaguely remember the website name, but i cant find it. Thanks a bunch.

 

[BigC]

http/aquariumwatertesting.com/AWT_Salt_Analysis_0208.pdf

 

[andywg]

The above link from BigC should not be taken at face value. They mixed salt by weight and as such all the measurements relate to different salinities for the test sample. I also recall the n number of samples was less than one would want to form any real idea of the differences.

 

[Bignose]

andywg makes a very good point. It is very, very hard to properly sample solids, like salt. Solids tend to segregate themselves, even just from the vibrations of day-to-day living (like cars on the roads, walking around the room etc.) A good example of this is the roll of pennies that always seems to float on the top of a pile of change. The small vibrations allow the loose change to fall underneath the roll of coins.

You have to use some very special equipment, something like a spinning riffler ( http/www.lavallab.com/sample-division/spinning-riffler.htm ), in order to sort the solids in a statistically random way. And, even, then, a large number of samples should be tested to try to minimize as much as possible any kind of biasing error in the sampling.

It is nowhere as easy as sampling a liquid.

 

[andywg]

I shall plead modesty here and point out that what bignose has said (which is a very interesting point, I didn't realise testing solids was such a problem) was not the main thrust of my argument.

My issue is with the way these test samples were mixed. They took a set weight of salt and added it to RO water. This produced variations in salinity (as salt will absorb moisture from the air) which means some of the samples tested were at salinities far lower than you would use it in the aquarium, making the tests somewhat meaningless.

 

[Dorkhedeos]

Thanks guys, I was just wanted to see to see the phosphate levels amongst the brands.