Sea Salt Question

[monodon]

I've got a quick question on something, forgive me if its ignorance on a basic thing but I haven't found an answer searching on my own.

Most people with salt-water aquariums, I assume, are using some of these products, like Instant Ocean or Red Sea, and most of these are synthetic or specially-formulated. I'm wondering, though, if anyone here (or if it is technically possible to do so) is using basic sea salt, simply the salt that is collected by evaporating the water from saltwater?

Would it work, and why or why not? Any input on this will be greatly appreciated.

[skinz78]

It should work but I wouldn't try it because you run the risk of impurity's in it. IE pollutants and such.

If you are fortunate enough to live by the sea where you can go out and get your own NSW without any polluting factors near by "mills, factorys, etc" then why not just take NSW and bring it up to tempature slowly for your system?

[Ninong]

I'm wondering, though, if anyone here (or if it is technically possible to do so) is using basic sea salt, simply the salt that is collected by evaporating the water from saltwater?

Would it work, and why or why not?

No, it won't work. Exactly why it won't work is complicated.

Off the top of my head, here are a few reasons that I can think of as to why it won't work:

• Pollution from fallout from the air.
• Pollution from bird droppings and other animal contamination.
• Pollution from chemical contamination caused by man.
• Crystallization of sea salt causes the magnesium to form on the surface of the crystals where it absorbs moisture from the atmosphere, dissolves and runs off.
• Sea salt from evaporation ponds undergoes a "washing" process to remove bird crap and other pollutants, but also to remove excess magnesium so that it will be whiter.

There are chemical processes that take place during the final stages when the brine turns to salt that make it impossible to reconstitute the same ionic balance by simply adding pure water. Obviously the loss of Mg is one of the most obvious ones. Other elements are gassed off during the final stages of evaporation. Sea salt from evaporation is 99.7% pure NaCl after it is washed. In fact, it can be made 99.95% pure NaCl.

If you want to try to scoop up some yourself late at night from a salt pond when no one is looking to avoid the washing process, you will end up with contaminated salt that still doesn't have the same elements as natural seawater because of the loss of magnesium and other elements.




P.S. -- Composition of natural seawater.

[monodon]

Thanks for the replies.

Actually, some sources I'm finding on bulk salt are making available the salt before it has been washed to purify the NaCl. Pollution would definitely be a concern, but I think it would be possible to find a source that wouldn't be chemically polluting the sea salt, thus minimizing the risk to an effective degree.

I do have a question though. You mention that it wouldn't reconstitute to the same ionic balance when adding it to pure water. However, if you weren't adding it to freshwater that has not been subjected to reverse osmosis or some kind of softening, wouldn't it be possible that the loss of magnesium and other elements would still be represented, if not to the full extent? Maybe enough to get by?

At least in this example, we're talking about huge volumes of water and not fish that are being kept for display and longevity. Of course, maintaining a balance as close as possible to NSW would still be desirable to ensure the least amount of stress and to encourage proper and full development (of shrimp). Making up for loss of crucial elements by adding them in separately would be an option as well.

Anyways, thanks for your informative reply. I've been doing a lot of research on this and eventually some trials will be run, so at some point in the future I should be able to post back on this with results. I've seen at least one example in which salt-water shrimp was raised successfully in water with a salinity of 1 ppt (as opposed to 35!), so I'm optimistic about being able to successfully accomplish this in a place where we have no direct source for NSW.

[monodon]

Also, do you know how much (if any), approximately, of sulfate is lost to the evaporation process? Any resources you know of that explain in fuller detail this chemical process?

[kgross]

The salt will not reconstitute as listed above. Some of the salts that are formed during the evap process are not easily soluble so they do not convert back to the ionic form. IE you will have calcium carbonate precipitation in the evap, calcium carbonate, will not desolve back into calcium ions and carbonate ions in RO/DI water even close to 100%.

Kim

[monodon]

Actually, RO/DI would not be used, hypothetically, but rather regular fresh-water - especially considering the impression I've gathered that calcium and magnesium would be lost in the evaporation process, but also due to the amount of water we're talking about.
Anyways, do either of you know of any resource that has much more detailed information regarding what precisely happens chemically as saltwater evaporates? I'm having trouble finding anything through searching yet. The idea is to figure out what would be lacking, what has changed, and finding a way to contribute something else to the water to compensate.
Any help would be greatly appreciated.