Ignorant salinity question

[Michael43]

is there a table or something available to gauge salinity in comparison to temp. Obviously salinity changes in comparison to temp. For instance I keep my temp around 75 degrees and my salinity usually reads around 34-34.5. What is my true salinity. I want to run the tank around 34.5 so I need to know what my apex and refractometer should read

 

[dragon99]

The Apex has an option to enable temp compensation.

The refractometer is almost certainly an ATC (auto temp correction), so you wouldn't really need to make any adjustments to the readings you are getting.

 

[Michael43]

Yes it's an atc. I never new the apex could do that. I will try and change it when I get home. Will it need recalibration?

 

[Randy Holmes-Farley Verified Community Expert]

Salinity does not change with temperature.

The measurement taken by various types of devices can change with temperature, and sometimes is automatically corrected (conductivity probes, for example, or ATC refractometers or swing arm hydrometers) and sometimes not (floating glass hydrometers, for example).

 

[Michael43]

I ask because I know salinity adjusts with temperature. So when is it right. My tank might be 75 degrees and 34.7 cond. It may warm up till 75.6-8 at times and the cond on my apex will go as high as 35.2. The actually cond/salinity can't be different from the temp can it? When the reading right?

 

[alyee5]

I ask because I know salinity adjusts with temperature. So when is it right. My tank might be 75 degrees and 34.7 cond. It may warm up till 75.6-8 at times and the cond on my apex will go as high as 35.2. The actually cond/salinity can't be different from the temp can it? When the reading right?

Higher temperature will increase ion mobility and hence conductivity...

This is from http://www.fondriest.com/environmen...ters/water-quality/conductivity-salinity-tds/

Sounds like you have an APEX...if you plug a temperature probe in the PM2 module and use the temp compensation and get a more accurate conductivity measurement....

Here is how to do it from BRS

 

[Randy Holmes-Farley Verified Community Expert]

I ask because I know salinity adjusts with temperature. So when is it right. My tank might be 75 degrees and 34.7 cond. It may warm up till 75.6-8 at times and the cond on my apex will go as high as 35.2. The actually cond/salinity can't be different from the temp can it? When the reading right?

The salinity doesn't change with temp. The "measured" conductivity does, and the device automatically compensates for that effect to product a corrected and reported conductivity, adjusted to conductivity at 25 deg C equivalent (at least that the standard). To do that, the conductivity device needs to know the exact temp of the measurement, so if the probes for temp and conductivity are separated, they both need to be in the calibration and/or test solutions.

FWIW, this temp correction is not perfect, so it is best to calibrate and measure reasonably close in temp to each other.