Hanna salinity checker vs refractometer

[Piece of reef]

Hey guys,

For the past 2 years ive been using my hanna salinity checker and everything seems fine, 1.025 salinity

I mixed some saltwater today and thought id get the old refractometer out and cross check, its been sitting in my cupboard for the past year or so,

I calibrated the refractometer with rodi water because i dont have the 35ppt fluid to calibrate it

When i checked my water it shows 1.027-28

Now i dont know what to believe, anyone have a similar situation or advice

I may go buy another refractometer tomorrow but thought id post here first to get some opinions

 

[liddojunior]

Did you also calibrate the Hanna?
You can’t compare them when their calibration isn’t to the same fluid.

I do think a refractometer is more accurate, while Hanna is more precise.

If you get 2 color identifier tools
Tool 1 calibrate to yellow-
Tool 2 calibrate to green-blue.
Then compare them when testing to yellow paper. You will get slightly different numbers.

Edit: Don’t buy a new tool, buy new calibration fluid. You’ll still have the same issue, except since you’ll calibrate it with RO water like the other you’ll believe the Hanna is the problem incorrectly

 

[Piece of reef]

Did you also calibrate the Hanna?
You can’t compare them when their calibration isn’t to the same fluid.

I do think a refractometer is more accurate, while Hanna is more precise.

If you get 2 tools and tell one tool this is paper is yellow-green. And you tell the other tool this paper is green-blue. Then ask them both how yellow is his paper they are going to different from each other because the reference is opposites

Yes after getting different results, i calibrated the hanna checker with the hanna fluid,
And it still showed 1.025

Nothing in my tank is showing stress, coral seems happy and open but i didnt want to wait untill something does happen then have regrets

 

[liddojunior]

Yes after getting different results, i calibrated the hanna checker with the hanna fluid,
And it still showed 1.025

Nothing in my tank is showing stress, coral seems happy and open but i didnt want to wait untill something does happen then have regrets

Did you calibrate the refract to the Hanna fluid?
I’m pointing out that they both need the same base standard calibration. The way these things work is how different is the tested fluid from the control fluid.
Also why would you say you don’t have 35ppt fluid to calibrate without turns out you do since the Hanna fluid is 35 ppt water

 

[Piece of reef]

Did you calibrate the refract to the Hanna fluid?
I’m pointing out that they both need the same base standard calibration. They way these things work is how different is the tested fluid from the control fluid.

No i didnt because the hanna fluid says "not to be used with refractometers"

I think because they use different methods of measuring,

 

[gbroadbridge]

Hey guys,

For the past 2 years ive been using my hanna salinity checker and everything seems fine, 1.025 salinity

I mixed some saltwater today and thought id get the old refractometer out and cross check, its been sitting in my cupboard for the past year or so,

I calibrated the refractometer with rodi water because i dont have the 35ppt fluid to calibrate it

When i checked my water it shows 1.027-28

Now i dont know what to believe, anyone have a similar situation or advice

I may go buy another refractometer tomorrow but thought id post here first to get some opinions

Is the refractometer a seawater device or designed for saline brine?

In any event a refractometer should be calibrated with a standard close to the fluid you are testing - in the this case it should be calibrated to a 35ppt standard.

Given an unknown refractometer, the Hanna conductivity tester will give more accurate results if calibrated correctly.

 

[gbroadbridge]

No i didnt because the hanna fluid says "not to be used with refractometers"

I think because they use different methods of measuring,

Correct.

A conductivity standard is not the same as a refraction standard unless they have been designed specifically for both types of devices.

You can easily DIY standards for both types of measurement.

https://reefkeeping.com/issues/2004-06/rhf/index.php

 

[Piece of reef]

Is the refractometer a seawater device or designed for saline brine?

In any event a refractometer should be calibrated with a standard close to the fluid you are testing - in the this case it should be calibrated to a 35ppt standard.

Given an unknown refractometer, the Hanna conductivity tester will give more accurate results if calibrated correctly.

Im not sure what type it is to be honest, it says atc on it, ill post a picture for you,

Ill try get some calibration fluid tomorrow and retest before i do a water change, incase i need to adjust

Thanks for the link, ill check it out now

 

[gbroadbridge]

Im not sure what type it is to be honest, it says atc on it, ill post a picture for you,

Ill try get some calibration fluid tomorrow and retest before i do a water change, incase i need to adjust

Thanks for the link, ill check it out now

The ATC refers to Automatic Temperature Compensation which is necessary as the result is dependent on temperature.

 

[liddojunior]

I wasn’t aware the Hanna Fluid was not appropriate, thought it was just saline water. My packets don’t say that.
But basically as pointed out, need to calibrate to 35ppt or it’s going to say different values.
So nothing surprising here, I also believe the Hanna is more trustworthy in this case

 

[gbroadbridge]

I wasn’t aware the Hanna Fluid was not appropriate, thought it was just saline water. My packets don’t say that.
But basically as pointed out, need to calibrate to 35ppt or it’s going to say different values.
So nothing surprising here, I also believe the Hanna is more trustworthy in this case

It's Potassium Chloride solution but you can make a DIY using table salt and RODI water.

Instructions in the above link.

 

[Piece of reef]

Thanks so much guys, ill get onto that calibration fluid and possibly get a 3rd check done at my lfs just to see the difference and be content

 

[jrill]

That's about the same result I get comparing the Hanna to the Tropic Marin hydrometer.

 

[Piece of reef]

That's about the same result I get comparing the Hanna to the Tropic Marin hydrometer.

So is the hanna checkers reading low ?

 

[jrill]

So is the hanna checkers reading low ?

Yes, it has been that way for the two years I've used it. While it always reads low its always consistent so I just factor that in and know where I need it to be. I calibrate once a month and always verify the difference with the Tropic Marin hydrometer.

 

[gbroadbridge]

Yes, it has been that way for the two years I've used it. While it always reads low its always consistent so I just factor that in and know where I need it to be. I calibrate once a month and always verify the difference with the Tropic Marin hydrometer.

How did you check the calibration of the hydrometer?

 

[Mr. Mojo Rising]

These threads are actually very common, if you use 2 devises, you will get 2 different measurements. Every device has a +/- percentage of error, no device that we use is 1000% accurate. Best is to just pick a device and stick to it

 

[jrill]

How did you check the calibration of the hydrometer?

I also have a refractometer that I cross checked the Tropic Marin with. Just by design the Tropic Marin is inherently more reliable.

 

[Piece of reef]

My hannas been consistent aswell for the past 2 years, but might get it down to 1.023-24, but as soon as i get time im going to get a third test done

 

[MBruun]

A hydrometer/floater cannot be calibrated since it measure salinity by the density of the water, and therefore more reliable than devices that needs to be calibrated. But as saltwater density depend on the temperature the result have to be calculated to give the actual salinity.
Calculator suggestions:

Salinitetsberegner

Omregning af enheder vedr. salinitet i saltvandsakvarie. Understøtter ledningsevne (mS/cm), salinitet (PSU og ppt), densitet (g/cm³) og relativ densitet.

reefapp.net

Aquarium Calculators

An index of useful aquarium calculators and converters.

www.hamzasreef.com