Natural sea water would seem to be the best choice for water changes in the marine aquarium. However, where can it be gotten? Much of the USA coastal areas are polluted. NSW shares a common concern with tap water purity in that the aquarist can't test for everything that might be in the water. There is some minimal exposure to acquiring disease and undesirable organisms through the use of NSW.
I've tested (analytical chemical analysis) NSW that was sold as 'not polluted.' I have found petroleum and fuel products in some of them. A rather humorous event was a person who went 25 miles out to sea and collected water in vats. The vat water showed petroleum products that matched those used by the boat. The person literally brought their own pollution to a relatively clean, unpolluted area of the ocean. This points out the need to control how the water is collected even if it is clearly done in a non-polluted part of the ocean/sea. This is not a recommendation to not use NSW. Just a recommendation to be wary of what can go wrong that the average aquarist is unable to verify by home test kits.
Choose your source water and NSW with consideration to the purity you need; the cost; value; the environmental impact (wasted water); and exposure and risks to impurities.
What source water or water do you use for your marine tank water changes? Please post your experience and what you use.
Link to this article:
http://www.reefland.com/forum/marine...ource-nsw.html
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