Salinity

[bang guy]

Sometime during the past 10 years hobbiests started thinking that Salinity and Specific Gravity are interchangeable. Why is that?
I'm even hearing experienced hobbiests advising new hobbiests to "get Salinity up to 1.026". This is just plain wrong.
Sorry for the rant.
Now back to our regularly scheduled programming...

 

[fbm]

I agree, I just thought that is what everyone calls it. Thought it was a industry slang or something like that.

 

[jrthomas40]

yeah i dont know what is up with that either...as a biologist i would like for people to know for the sake of knowing...when talking about salinity that you talking about parts per million and specific gravity is relatively the density

 

[gwh57]

What is the specific gravity and salinity of natural sea water? :thinking:
That is what I want my tank at.

 

[zookeypr12]

Originally Posted by Bang Guy
Sometime during the past 10 years hobbiests started thinking that Salinity and Specific Gravity are interchangeable. Why is that?
I'm even hearing experienced hobbiests advising new hobbiests to "get Salinity up to 1.026". This is just plain wrong.
Sorry for the rant.
Now back to our regularly scheduled programming...

Thanks for clearing that up for me.....being a newbie at this, I was wondering why it was referred to as 2 different names
I just keep learning and learning from this board

 

[gwh57]

OK, Salinity and Specific Gravity are not interchangeable terms, but if we know what them mean is that important? :thinking:

 

[dogstar]

Salinity at 1.026 would be fine for brackish if its a percentage....haha
Salinity is the measurement of the amounts of salts ( all the different mineral/elements ions ) that is in water other than the H2O. It can be measured by giveing a percentage like 3.5, or parts per thousand like 35 ppt. The salinity of pure water ( distilled ) is 0.00. Changes in temperatures does not change the Salinity.
Specific gravity is measureing the density of a given sample of water compared to pure water. Pure water has a S. G. of 1.000. A sample of water with a S. G. of 1.026 is 1.026 times more dense than pure water. This ( density ) is what effects the buoyancy ( swingarm on a hydrometer ) and presure and metablisim of animals in the water. Changes in temperatures can change the S. G.
This is how I understand it....

 

[jrthomas40]

the salinity in the gulf here around the mobile bay its about 27-30 ppm i dont know what that equates to in SG...and i think the real ocean is about 32 or maybe a tad higher

 

[bonebrake]

I have used both names interchangeably, but understand the difference.
I will use the correct terminology from now on.
:thinking:
Salinity: 35 ppt NaCl
Specific gravity: 1.026 g/mL
:joy:

 

[neoreef]

Originally Posted by jrthomas40
the salinity in the gulf here around the mobile bay its about 27-30 ppm i dont know what that equates to in SG...and i think the real ocean is about 32 or maybe a tad higher
You mean ppt, or parts per thousand. The salinity of the real ocean is around 35 ppt.

 

[isistius]

Originally Posted by Dogstar
Salinity at 1.026 would be fine for brackish if its a percentage....haha
Salinity is the measurement of the amounts of salts ( all the different mineral/elements ions ) that is in water other than the H2O. It can be measured by giveing a percentage like 3.5, or parts per thousand like 35 ppt. The salinity of pure water ( distilled ) is 0.00. Changes in temperatures does not change the Salinity.
Specific gravity is measureing the density of a given sample of water compared to pure water. Pure water has a S. G. of 1.000. A sample of water with a S. G. of 1.026 is 1.026 times more dense than pure water. This ( density ) is what effects the buoyancy ( swingarm on a hydrometer ) and presure and metablisim of animals in the water. Changes in temperatures can change the S. G.
This is how I understand it....
that's dead on.

 

[teen]

Originally Posted by jrthomas40
the salinity in the gulf here around the mobile bay its about 27-30 ppm i dont know what that equates to in SG...and i think the real ocean is about 32 or maybe a tad higher
in marine bioology we were always taught that the salinity of NSW ranges from 33-36 ppt. i suppose it depends on how close you are to land considering run opff rain water and streams or rivers that run off into the ocean.

 

[isistius]

Originally Posted by teen
in marine bioology we were always taught that the salinity of NSW ranges from 33-36 ppt. i suppose it depends on how close you are to land considering run opff rain water and streams or rivers that run off into the ocean.
that's correct.

 

[reefkprz]

Originally Posted by Bang Guy
Sometime during the past 10 years hobbiests started thinking that Salinity and Specific Gravity are interchangeable. Why is that?
I'm even hearing experienced hobbiests advising new hobbiests to "get Salinity up to 1.026". This is just plain wrong.
Sorry for the rant.
Now back to our regularly scheduled programming...

I have wanted to say that sooo many times.