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By Steven By Steven Pro
There have been a number of studies done to try to find the best artificial salt mix for aquarium keeping: Chemical Analyses Atkinson,
Marlin & Craig Bingman. 1999. “The Composition of Several Synthetic Seawater
Mixes.” Aquarium Frontiers, March 1999.
http://web.archive.org/web/20001215070800/http:/ Hovanek, Dr.
Timothy & Jennifer Coshland. 2002. “A Chemical Analysis of Select Trace Elements
in Synthetic Sea Salts and Natural Seawater.” Advanced Aquarist, September 2004.
Marulla, Mathew & Thomas O’Toole. 2005. “The Inland Reef Aquaria Salt Study, Part I.” Advanced Aquarist, November 2005. http://www.advancedaquarist.com/2005/11/aafeature1 Marulla, Mathew & Thomas O’Toole. 2005. “The Inland Reef Aquaria Salt Study, Part II.” Advanced Aquarist, December 2005. http://www.advancedaquarist.com/2005/12/aafeature1 Biological Analyses Borneman,
Eric. 2006. “Sea Salts, Part One: A Review and a New Study to Determine Their
Effects on Reef Aquarium Inhabitants.” Reef Hobbyist Online, May 2006.
Borneman, Eric & Kim Lowe. 2006. “Sea Salts, Part Two: The M.A.R.S.H. Salt Study.” Reefkeeping, September 2006. http://reefkeeping.com/issues/2006-09/eb/index.php Hovanek, Dr. Timothy, Elana Toy, Jennifer Westerlund, & Jennifer Coshland. 2005. “The Toxicity of Freshly Mixed Sea Salts and Natural Seawater to the Development of White Sea Urchin (Lytichinus pictus) Larvae.” Advanced Aquarist, March 2005. http://www.advancedaquarist.com/2005/3/aafeature/ Shimek, Dr.
Ronald. 2003. “The Toxicity of Some Freshly Mixed Artificial Sea Water: A Bad
Beginning for a Reef Aquarium.” Reefkeeping, March 2003. All of these experiments have their own inherent limitations. The chemical analyses are prohibitively expensive for most aquarists to attempt. Because of the cost associated with them, these tests have routinely had very small sample sizes. And while the biological analyses are not quite as expensive, they are certainly not cheap either and can be very time consuming or suffer from small sample sizes. So, I was pondering the predicament of evaluating salt mixes one day trying to come up with a solution (yes, I am that much of a fish geek that I routinely think about aquarium related issues while driving around for work) when my thoughts wandered to a project called Reef Check. About Reef Check (www.reefcheck.org): “Founded in 1996 by marine ecologist Dr. Gregor Hodgson, the Reef Check Foundation is an international non-profit organization dedicated to conservation of two ecosystems: tropical coral reefs and California rocky reefs. With headquarters in Los Angeles and volunteer teams in more than 80 countries, Reef Check works to create partnerships among community volunteers, government agencies, businesses, universities and other non-profits. Reef Check goals are to: educate the public about the value of reef ecosystems and the current crisis affecting marine life; to create a global network of volunteer teams trained in Reef Check's scientific methods who regularly monitor and report on reef health; to facilitate collaboration that produces ecologically sound and economically sustainable solutions; and to stimulate local community action to protect remaining pristine reefs and rehabilitate damaged reefs worldwide.” Basically, this program works by giving recreational divers and local villagers simple standards, some training, and instruments and in this way Reef Check is able to network together a very large number of volunteers who in turn can collect an extreme amount of data. This large data set can give fairly accurate numbers because the outliers sort of disappear in the face of the large quantity of raw figures. I would like to see us marine hobbyists attempt to do this in regards to salt mixes (and it would also be valuable to see other hobbyists repeat my activated carbon and phosphate test from the last issue of Conscientious Aquarist).
My Standards For The Testing: As I said from the outset, I intend for others to replicate my testing. I do not want anyone to take this limited evaluation of salt mixes and switch from their chosen brand because of these results. To that end, I created a simple set of standards that I believe a large number of accomplished hobbyists can follow. The number one rule is, use a full bag of salt mix. If you intend to mix 50 gallons of water, buy a 50 gallon bag, not a 160 gallon bucket and scoop out the necessary amount from it. I know a lot of people do that, use only a portion of the salt mix in a given package, but this has always bothered me. For instance, I have bought quite a number of supposedly mixed-bed DI cartridges, but the two resins have completely separated in the cartridge. I believe this separation is due to agitation during shipping. This has always concerned me when it comes to salt mixes. How can we be sure this same sort of occurrence does not also happen with salt mixes? Some bags of salt come packed tight with little air and are solid as a brick, while other bags I have gotten are loose and one can feel the salt tumbling around in the bag. Salts are complex mixtures of a variety of compounds which could possibly settle and shift in the bag resulting in varying compositions when sampled and mixed. So, for my testing and for anyone that wants to replicate this, use only full and complete packages. The second rule is a simple one, use only DI water. The varying compositions of tap water around the country could significantly affect the results one gets in the testing. By using only DI water, we can eliminate that variation. Furthermore, the DI water should be aerated for 24 hours prior to adding the salt mix and that mixture should be blended for an additional 24 hours before any testing is done. As to what to test with, I chose Salifert test kits. They are commonly used, reasonably priced, have a good reputation, and are widely available. There are better test kits and electronic meters out there, but these are less common and more expensive. As I said, I want to get the greatest number of participants, so I selected Salifert. The last rule is to mix the salt to 1.025 specific gravity and verify that number with a true seawater refractometer that has been calibrated with both pure water as well as a natural seawater reference solution.
The Easy Ones: In my tests, I never found any traces of ammonia, nitrite, nitrate, or phosphate. I also never had any precipitate form. I have seen numerous people report finding strange precipitates appear in the bottom of their salt mixing vats. Some of these, based on the description of a white powdery substance, sound like simply calcium carbonate has fallen out of solution. Others though have been described as brownish, and I don’t know what that could be. Either way, I found none of these types of precipitates form in any salt mix I used. pH Levels:
As one can see from the chart, most all of the salt mixes had a low pH, between 7.5 and 7.7. But, that does not surprise me. Every salt I have ever used when mixed with deionized water always resulted in a solution with a depressed pH. That is just par for the course as far as I am concerned and is easily rectified using commonly available commercial buffer preparations. Now, I do realize some people have reported elevated pH levels, possibly detrimentally high. I don’t know why it is that my mixed water is always low except to say I always aerate my DI water for 24 hours prior to adding salt and I then mix the salt and water for an addition 24 hours before testing it. There were two salt mixes that varied from the others. Instant Ocean sample number two when the pH was tested resulted in a color not on the chart. I would describe it best as an orange-red color. I will discuss this more later. The other one is the Seachem Reef salt sample. It mixed to a pH of 8.1 right out of the bag without any adjustment. Seachem is reported as using a higher level of borate, which would certainly affect the pH level and buffer it up. Calcium Levels:
Almost every bag in my testing had a calcium level between 340 and 360 ppm. Again, that also does not concern me too much. It can be bumped up easily enough if one desires, but personally, I am quite content to have my calcium running steadily at around 350-375 ppm along with an elevated alkalinity level. I prefer higher alkalinity over higher calcium because I prefer to run my aquariums with a strong and steady pH. The two brands outside of this range were Oceanic at 470 ppm, which has a reputation for higher calcium levels, and Seachem Reef salt at 400 ppm. Alkalinity Levels:
The final parameter I wish to discuss is alkalinity. In this instance, there was no clear pattern or small range which most brands fell inside. As I stated previously, my personal preference is to run a higher alkalinity, 3.5 meq/l or greater. Because of this, I was pleased to use Instant Ocean #1, both Reef Crystals samples, Seachem Reef salt, and the regular Tropic Marin as these were all close enough in my opinion for my preferences. I did not like the lower alkalinity of Oceanic nor Tropic Marin Pro Reef, but both are near natural seawater parameters (Holmes-Farley, 2004) and I also understand that certain reef aquarium techniques do prefer alkalinity levels closer to natural seawater. Conclusions: I really don’t have too many conclusions to draw. As I stated, most brands that I tested, I only examined a single bag. Perhaps after we test a couple of hundred of each brand, we might be able to make some determinations as to how the various brands are formulated. Atkinson,
Marlin & Craig Bingman. 1999. “The Composition of Several Synthetic Seawater
Mixes.” Aquarium Frontiers, March 1999.
http://web.archive.org/web/20001215070800/ Borneman,
Eric. 2006. “Sea Salts, Part One: A Review and a New Study to Determine Their
Effects on Reef Aquarium Inhabitants.” Reef Hobbyist Online, May 2006.
Borneman, Eric & Kim Lowe. 2006. “Sea Salts, Part Two: The M.A.R.S.H. Salt Study.” Reefkeeping, September 2006. http://reefkeeping.com/issues/2006-09/eb/index.php\
Holmes-Farley, Randy. 2004. “Reef Aquarium Water Parameters.” Reefkeeping, May
2004. Hovanek, Dr.
Timothy & Jennifer Coshland. 2002. “A Chemical Analysis of Select Trace Elements
in Synthetic Sea Salts and Natural Seawater.” Advanced Aquarist, September 2004.
Hovanek, Dr. Timothy, Elana Toy, Jennifer Westerlund, & Jennifer Coshland. 2005. “The Toxicity of Freshly Mixed Sea Salts and Natural Seawater to the Development of White Sea Urchin (Lytichinus pictus) Larvae.” Advanced Aquarist, March 2005. http://www.advancedaquarist.com/2005/3/aafeature/ Marulla, Mathew & Thomas O’Toole. 2005. “The Inland Reef Aquaria Salt Study, Part I.” Advanced Aquarist, November 2005. http://www.advancedaquarist.com/2005/11/aafeature1 Marulla, Mathew & Thomas O’Toole. 2005. “The Inland Reef Aquaria Salt Study, Part II.” Advanced Aquarist, December 2005. http://www.advancedaquarist.com/2005/12/aafeature1 Shimek, Dr.
Ronald. 2003. “The Toxicity of Some Freshly Mixed Artificial Sea Water: A Bad
Beginning for a Reef Aquarium.” Reefkeeping, March 2003.
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