Issue with GHL salinity measurements

[miksuv]

Hello

A quick question from me, i have a new P4 and i calibrated the Salinity twice, and on both times i am getting readings that are much higher than my just calibrated Hanna checker. One thing i also noticed that my 3 other temp probes were showing different than the GHL probe, this i adjusted manually.

Calibration 1: Calibration fluid in the tank - Normal calibration process
Calibration 2 Measure calibration fluid with P4 probe and use the value for the calibration process.

In both cases the P4 sensor is showing 36.1-36.3. And my Hanna that was calibrated (twice calibrated with their fluid) shows 34.8PSU. I would understand a small deviation but we are talking of a much larger difference.

@Vinny@GHLUSA what would be your guidance?

 

[arking_mark]

Hello

A quick question from me, i have a new P4 and i calibrated the Salinity twice, and on both times i am getting readings that are much higher than my just calibrated Hanna checker. One thing i also noticed that my 3 other temp probes were showing different than the GHL probe, this i adjusted manually.

Calibration 1: Calibration fluid in the tank - Normal calibration process
Calibration 2 Measure calibration fluid with P4 probe and use the value for the calibration process.

In both cases the P4 sensor is showing 36.1-36.3. And my Hanna that was calibrated (twice calibrated with their fluid) shows 34.8PSU. I would understand a small deviation but we are talking of a much larger difference.

@Vinny@GHLUSA what would be your guidance?

Per the previous discussion, I believe that the only # that will correlate with other meters is GHL density reading...

Per reef calculators, 53ms/cm = 35ppt (35psu) and 1.0234 kg/l (1.0264 sg)

So to get a match, you need to convert GHL density to meters equivalent.

So if your Hanna is measuring 34.8psu, your GHL density should be 1.0232kg/l.

Just curious if this is true for you.

 

[arking_mark]

Hello

A quick question from me, i have a new P4 and i calibrated the Salinity twice, and on both times i am getting readings that are much higher than my just calibrated Hanna checker. One thing i also noticed that my 3 other temp probes were showing different than the GHL probe, this i adjusted manually.

Calibration 1: Calibration fluid in the tank - Normal calibration process
Calibration 2 Measure calibration fluid with P4 probe and use the value for the calibration process.

In both cases the P4 sensor is showing 36.1-36.3. And my Hanna that was calibrated (twice calibrated with their fluid) shows 34.8PSU. I would understand a small deviation but we are talking of a much larger difference.

@Vinny@GHLUSA what would be your guidance?

Pee the previous discussion, I believe that the only # that will correlate with other meters is their GHL density reading...1.0233 kg/l =

Oops..

 

[arking_mark]

Since I actually just re-calibrated my GHL conductivity probe last week (measurements were runnng a little high) and my tank has completed adjustment to target...

What I trust: High-precision Hydrometer

My calibrated GHL:

My Hanna which always reads a little low...

GHL density # is perfect match with High-precision hydrometer per conversion calculator https://reefapp.net/en/salinity-calculator

 

[Member No 1]

Since I actually just re-calibrated my GHL conductivity probe last week (measurements were runnng a little high) and my tank has completed adjustment to target...

What I trust: High-precision Hydrometer

For my own sanity, what would you consider the hydrometer to be reading in this picture?

 

[arking_mark]

For my own sanity, what would you consider the hydrometer to be reading in this picture?

Meniscus is at 1.0262 almost on the dot. It's harder to read the actual water level which is the actual reading. I estimate it's closer to 1.0263

 

[Jgoal55]

Since I actually just re-calibrated my GHL conductivity probe last week (measurements were runnng a little high) and my tank has completed adjustment to target...

What I trust: High-precision Hydrometer

My calibrated GHL:

My Hanna which always reads a little low...

GHL density # is perfect match with High-precision hydrometer per conversion calculator https://reefapp.net/en/salinity-calculator

Late to this thread, but as an FYI, I’m finding this to be the case as well when trying to match the high-precision TM floating hydrometer.

My hydrometer was showing slightly high and my GHL low. I recalibrated the probe and my PSU went to where expected, but the conversion (using the same calculator you linked) still didn’t match the SG shown on the hydrometer.

Changed to density then ran conversion and it’s a spot on match to the hydrometer.

I’ll probably stick to using density as now I know the number I need to match the hydrometer which I trust most.

Also, need to lower my salinity a bit. Lol