Reef Chemistry Question of the Day #31 Hyposalinity

Randy Holmes-Farley

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Reef Chemistry Question of the Day #31

Well have an easier one for the Columbus Day holiday...

If an aquarist wanted to produce a hyposaline solution with a specific gravity of about 1.009, that can be best accomplished by mixing which of the following solutions?


A. Mixing 90% pure fresh water with 10% seawater (sg = 1.0264)
B. Mixing 66% pure fresh water with 34% seawater (sg = 1.0264)
C. Mixing 33% pure fresh water with 67% seawater (sg = 1.0264)
D. Mixing 13% pure fresh water with 87% seawater (sg = 1.0264)

Good luck!















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Randy Holmes-Farley

Randy Holmes-Farley

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Yes, well, all my blabbering and you guys are exactly right. The chemistry does agree with the math, and you had the right math. :)

The answer is..... B. Mixing 66% pure fresh water with 34% seawater (sg = 1.0264)

Mixing 0.34 parts of water with a sg of 1.0264 and 0.66 parts of water with a sg of 1.0000 yields a sg of 0.34 x 1.0264 + 0.66 x 1.0000 = 1.0090 :)

So, if you intend to treat a fish with hyposalinity, make up a solution of about 1 part tank water and 2 parts RO/DI, and then adjust a small amount from there, up or down, using more tnak water or Ro/DI water to get to 1.009. :)
 
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