Conductivity probe vs refractometer?

My ghl probe is reading 29.8 PSU and my Hanna Salinity checker reading at

42.7 PSU; I calibrated both today

I also checked with my VEEGEE STX 3 and reading at 43. I am guessing need new conductivity probe
 
Are you sure the units are right?
35psu = 35ppt = 1.026sg = 53mS/cm

Your 29.6psu = 1.0224sg = 45.972mS/cm

If in fact you do have a PSU of 42.7-43 your SG would be 1.0325 or 63.654mS/cm

From NASA website:
"Practical Salinity Unit
Used to describe the concentration of dissolved salts in water, the UNESCO Practical Salinity Scale of 1978 (PSS78) defines salinity in terms of a conductivity ratio, so it is dimensionless. Salinity was formerly expressed in terms of parts per thousand (ppt) or by weight (parts per thousand or 0/00). That is, a salinity of 35 ppt meant 35 pounds of salt per 1,000 pounds of seawater. Open ocean salinity is generally in the range from 32 to 37."
For all practical purposes, salinity in PSS or PSU has the same numerical value as salinity in ppt.
 
It could be.
Did you allow the probe to setting a few days before calibration?
Was the calibration fluid the same temp?
Did you use automatic temp calibration or did you enter the temp manually?
Rinse well? Dried off good?
Is the fluid fresh and not contaminated?

Mine reads slightly lower than 2 calibrated refractometers.
I don't use it for control, but track trends.

One thing I've done in the past is, once you are 100% sure what your tank
is reading, calibrate the probe to the tank instead of the fluid. Then see if it holds or varies. You can prove if the probe is going or is bad.
 
Ok, I recalibrated this time I kept calib solution in tank same time and calibrated a lot quicker and now probe reading 58.5ms; Hanna 39.7; refractometer 1.030 seems good now correct?

I am guessing temp was issue
 
Ok, I recalibrated this time I kept calib solution in tank same time and calibrated a lot quicker and now probe reading 58.5ms; Hanna 39.7; refractometer 1.030 seems good now correct?

I am guessing temp was issue

Seems to be more inline now.
 
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