Calcium Rising without Dosing!!

[arking_mark]

Oceanographers generally use conductivity. The practical salinity scale (PSU) is actually defined by conductivity. Hydrometers (and refractometers) are mostly a hobbyist thing.

So I have 2 conductivity meters that provide different measurements after calibration. Interestingly enough, the GHL's calculated density marches the High-precision Hydrometer. However, the GHL's conductivity readings don't match what the calculated SG should be.

So if I trust GHL's density which matches the High-precision Hydrometer, I need to drop my salinity to get into the 1.0264 SG range. Or do I go with GHL's conductivity reading...@53 would puts my High-precision Hydrometer somewhere over 1.028 SG and my Hanna over 37ppt.

Thoughts?

 

[Randy Holmes-Farley Verified Community Expert]

So I have 2 conductivity meters that provide different measurements after calibration. Interestingly enough, the GHL's calculated density marches the High-precision Hydrometer. However, the GHL's conductivity readings don't match what the calculated SG should be.

So if I trust GHL's density which matches the High-precision Hydrometer, I need to drop my salinity to get into the 1.0264 SG range. Or do I go with GHL's conductivity reading...@53 would puts my High-precision Hydrometer somewhere over 1.028 SG and my Hanna over 37ppt.

Thoughts?

Did they correctly read the same calibration fluid correctly after calibration?

I'm not familiar with the GHL. But with some aquarium controllers, there are problems of uncertain origin, and one issue may be remote temperature measurement.

Temp must be the same as the standard, or properly accounted for.

 

[arking_mark]

Did they correctly read the same calibration fluid correctly after calibration?

I'm not familiar with the GHL. But with some aquarium controllers, there are problems of uncertain origin, and one issue may be remote temperature measurement.

Temp must be the same as the standard, or properly accounted for.

They were all correctly calibrated using their calibration fluids and then read correctly afterward. Hence my troubles. GHL is particularly frustrating because their EC measurement has different values you can display...that don't seem to align with expected calculated values.

Salinity Measurement Troubles...

So I've been dealing with a couple of meters that all give me different readings after being calibrated: GHL = 34.6 psu, 52.7mS, 1.0245kg/l Hanna = 35.4ppt Other probe = 37.3ppt I bought a Tropic Marin Precision Hydrometer to establish ground truth... Tropic Marin Precision Hydrometer: 1.02775...

www.reef2reef.com

 

[Randy Holmes-Farley Verified Community Expert]

They were all correctly calibrated using their calibration fluids and then read correctly afterward. Hence my troubles. GHL is particularly frustrating because their EC measurement has different values you can display...that don't seem to align with expected calculated values.

Salinity Measurement Troubles...

So I've been dealing with a couple of meters that all give me different readings after being calibrated: GHL = 34.6 psu, 52.7mS, 1.0245kg/l Hanna = 35.4ppt Other probe = 37.3ppt I bought a Tropic Marin Precision Hydrometer to establish ground truth... Tropic Marin Precision Hydrometer: 1.02775...

www.reef2reef.com

What standard did you use?

 

[Randy Holmes-Farley Verified Community Expert]

In a conductivity device that has multiple possible reading units, always use conductivity as that is the natural unit measured. Anything else requires calculation that may or may not be done correctly.