Question on Refractometer Use

[sov82]

I just got my refractometer. Just a quick question...
When you put the drops of water onto it, do you put the drops ontop of the glass flap or underneath the glass flap?
Thanks.

 

[goldenboy]

3 drops underneath...

 

[lionfish12]

:yes:

 

[sov82]

Ya I just figured that out...didnt get a reading with it on theoutside....duh...
Tank was at 29ppt...could this be why I have been suffering gradual invert loss?

 

[goldenboy]

I keep my tanks salinity just over 1.020

 

[bang guy]

Originally posted by goldenboy
I keep my tanks salinity just over 1.020
That's pretty much just fresh water. Salinity really needs to be around 35ppt.

 

[goldenboy]

That's pretty much just fresh water

My tanks are right around 1.023. They can run high closer to 1.025, but I try to keep it lower. I should've specified more. But freshwater? 35 ppt is close to 1.026. Isn't that a little high for inverts?

 

[eagle1]

Bang Guy's explanation to a similiar question I had:
"Refractometers measure salinity, not specific gravity. Saltwater hobbiests should have no interest in S.G. if they have a refractometer.
The descrepancy is because S.G. changes with temperature and salinity does not (not significantly anyway).
Any scale that equates salinity with specific gravity is only accurate at one specific temperature.
Sea water is about 35ppt. So use the PPT scale and ignore the S.G. scale. I do not understand why they even put the S.G. scale on refractometers. You purchased an instrument that precisely measures salinity. It's an outstanding investment.
So bottom line:
35ppt for saltwater aquariums.
14ppt for hyposalinity to kill parasites."
Hope this helps.