View Full Version : Precipitation of Natural Sea Water (NSW) Carbonate cycle?

12/11/2010, 11:44 AM
There is a heated discussion regarding NSW in another thread. And I'd like to get your advice.

I've been using NSW for over a year and I've never had any precipitate particles in any of my containers. This includes a 300g storage container and a 60 gallon drum that I use on a weekly basis for water changes.

My argument is that NSW does not precipitate the way synthetic salt mixes can.

Can any chemist experts chime in. A fellow reefer feels that there is something called the "carbonate cycle" responsible for precipitation in our oceans. Has anybody heard of this?

Thanks for your help,

0scar M.

Link to thread in question: http://www.reefcentral.com/forums/showthread.php?t=1944569

12/11/2010, 03:22 PM
Both NSW and synthetic salt water contain suspended precipitates. The finer the suspended precipitates the longer they will stay in suspension. Wave action and currents can keep larger particles suspended and when it becomes still the larger particles will sink to the bottom quicker. Due to local high pH created when mixing synthetic salt mix, it is not uncommon to have precipitation occur & some of it will be larger in size and sink quickly.

Depending on where you take NSW, the suspended elements in it can differ, especially if the water is taken from polluted areas close to human activity. Many hobbyists use filters to remove some of the suspended particles to prevent from adding them to their tanks.

FWIW, suspended plastic particles are now found everywhere in the ocean even out to the farthest possible place from land. ;)

Samples taken from the deep ocean can look like this:


12/11/2010, 04:06 PM
Tanks for chiming in I appreciate the info. My experience before I switched to NSW was such that my containers I used for mixing my salt with RO/DI water would need a vinegar bath about once every couple of months due to the precipitation of various elements.

Now that I've been using NSW for over a year, I have not had to clean any of my containers since making the switch. This is why I have a hard time believing that precipitation occurs with NSW. My idea is that NSW is well balanced and contains all the elements in perfect equilibrium.

Thanks again for taking the time to post.

12/11/2010, 04:28 PM
I don't look at the precipitates found in the bottom of salt mix containers as a big deal.

The NSW if taken from clean areas of the ocean can have advantages of lower heavy metal content vs synthetic mixes which are quite high in its content. A plus for clean NSW. ;)

The negative with clean NSW are the organisms and micro-organisms that it may possibly contain like parasitic organisms, bacteria, cyanobacteria, dinos, algae, viruses.....etc. If NSW is taken form polluted areas and many hobbyists have no idea where their's come from, this can have negative effects as well. The filtering that many lfs put NSW through will not remove these nasty elements NWS can contain. :)

Personally I would take my chances with synthetic salt mixes vs NSW even if I was close enough to the water. To be honest, I would have no idea how far out I would have to go to get clean ocean water without being able to run expensive tests to determine this. ;)

12/11/2010, 04:43 PM
I assume this is why so many municipal aquariums (with millions of gallons in their systems) located on the ocean still use synthetic salt mixes. :)

12/11/2010, 04:47 PM
Yes NSW and even your tank has a carbonate cycle, only really called the Carbon Cycle, as does a lake, stream, pond etc.. Any chemical oceanography book has a whole chapter or two dedicated to it, i.e., Carbon Cycle and often with a chapter called Carbonate Chemistry or just CO2. Trying to compare the two is like trying to compare apples and oranges. Depth and sift in depth temp, pressure and the rain down of carbonate organisms are big things in the ocean and not your tank.

The reason you do not see precip particles / say, is that you are not mixing a salt. If you took a small piece of the ocean or a lake and dumped in some salt mix you will get some precip, as you super saturated that small area with "salts" just like a bucket. However, if I mix a salt and them siphon out the mixed seawater after a day or two you will not see and "particles" or have precip taking place anymore just like your NSW.

Here let me help you :D

Ocean Carbonate Cycle (http://lmgtfy.com/?q=ocean+carbonate+cycle)

A good review with lots of diagrams

12/11/2010, 05:07 PM
As a side note, a Hawaii Aquaculture production center is using natural seawater but taken from about a mile out and 3,000' down:

Deep Pipelines for Aquaculture
55” Seawater Supply System

Makai has designed for the State of Hawaii a larger warm and cold-water intake system for supplying both cold and warm water for aquaculture and ocean energy systems. Makai had full responsibility for the pipelines and pump station from the survey through to the final design plans and specifications. Estimated construction cost of the seawater supply system is 13 million dollars.

Profile of the 55” diameter polyethylene deep-water intake pipeline (click to enlarge)

The 55” seawater supply system is a dual ocean intake. One pipeline takes in seawater from a depth of 80’ and supplies over 50,000 gpm on shore. A second pipeline, approximately 10,000’ long and extending to a depth of 3000’ brings in 27,000 gpm of seawater at 4 deg C. Each pipeline is 55” OD and primarily consists of polyethylene pipe.

The full length of this 6000' long pipeline was laid on the bottom using the controlled flooding and submerging techniques used in the past. This pipeline, however, used this technique to a conservatively greater depth. The pipeline was flooded from the shore end to the offshore end, and the bitter end was lowered with a cable to the sea floor. The submerging and lowering of the pipeline took less then 12 hours.

The pipeline was smoothly and efficiently installed in October, 1988. The pipeline was inspected the following December proving that the pipe alignment and pendant arrangement is as designed.