Mail ordered corals and the salinity of the water they came in is pretty high - is that common?

[dedragon]

did you use calibration solution at 1.026? I got stuff from aqua sd and the salinity was low (1.021-1.022) which i found weird

 

[dedragon]

Some please help me here … seem to remember (from a lonnnng time ago) that temperature could affect salinity (or am I hallucinating) … if the water heated up or cooled in shipping … could that have caused a salinity swing?

good question patient. at what temp was the salinity measured? i have found if i even hold my refractometer for a while and it heats up a little and results can change

 

[Apollo7235]

Someone please help me here … seem to remember (from a lonnnng time ago) that temperature could affect salinity (or am I hallucinating) … if the water heated up or cooled in shipping … could that have caused a salinity swing?

You're definitely right! Specific gravity is a relative measure of density and density changes with temperature and pressure. That being said, I have no idea how much this could affect the readings we take, but it could be the issue here!

 

[Garf]

http://reefkeeping.com/issues/2006-12/rhf/#6

 

[Patientman]

http://reefkeeping.com/issues/2006-12/rhf/#6

Thank you Garf!

 

[Randy Holmes-Farley]

Right, I'm not talking about RODI, but the distilled water you can buy from the store.

Same issue. A brine refractometer (as opposed to the more rarely purchased true seawater refractometer) will necessarily be slightly off if calibrated in pure fresh water of any type. That is because it was not made for seawater, but for pure NaCl solutions.

 

[Randy Holmes-Farley]

You're definitely right! Specific gravity is a relative measure of density and density changes with temperature and pressure. That being said, I have no idea how much this could affect the readings we take, but it could be the issue here!

Most refractometers sold to hobbyists are ATC, and Automatically Compensate for Temperature changes.

 

[Apollo7235]

Most refractometers sold to hobbyists are ATC, and Automatically Compensate for Temperature changes.

That explains the 'ATC' on my refractometer, haha! Great to know. Thank you!

 

[Just John]

Most refractometers sold to hobbyists are ATC, and Automatically Compensate for Temperature changes.

This is what I have.

did you use calibration solution at 1.026? I got stuff from aqua sd and the salinity was low (1.021-1.022) which i found weird

Yes it was at 1.026 but from a different company.

 

[Just John]

good question patient. at what temp was the salinity measured? i have found if i even hold my refractometer for a while and it heats up a little and results can change

good question patient. at what temp was the salinity measured? i have found if i even hold my refractometer for a while and it heats up a little and results can change

77 deg.

 

[shred5]

I have had so many problems with calibration fluids for refractometers. I have a ton of bottles and most read different.
Your bottle of calibration fluid may be off.

 

[Just John]

I may make up one myself to see what I get.