Hanna salinity checker Issues may be their calibration fluid

[Randy Holmes-Farley Verified Community Expert]

Many folks find the Hanna reads low. One way that could happen is if their calibration fluid is off, and that appears it may be the case.

If you have a Hanna, I’d make a diy or get a better brand calibration fluid, such as Hach.

This link shows a test:

https://www.reef2reef.com/threads/salinity-checker.1131780/page-2#post-14113856

 

[rtparty]

I’d think you would need Hanna packets from more than just one batch. Of course packets from the same batch are likely to read the same

I think DIY solutions are the only way one can reliably calibrate any of these checkers

 

[exnisstech]

Id help out I binned mine. They were ok if i calibrated it with a known salinty water source. I mix water to 1.025 verified with a TM hydrometer which is all I have but seems to be accurate. I then calibrated the Hanna to 1.025 using that saltwater and it would match when I tested my tanks. Mine would drift more than I liked so I quit using them. Mine always read 0.002 lower than the hydrometer if I used Hanna's fluid. Same results using 2 different testers with different batches of fluid.

 

[BriDroid]

I’ve wanted one for a while now, but always decide at the last minute to not pull the trigger. Between my $14 refractometer that holds a calibration like a $1M and Randy’s DIY calibration solution, it’s all I really need.

 

[NanoSteam]

Yes I had the same experience, reads low compared to my VeeGee refractometer and Tropic Marin glass hydrometer. Also the fact the salt was mixing at much lower parameters let me know the salinity was off.

I did calibrate it with a known good solution and it works now but I never go for it, kind of a hassle to always have clean RODI water in a cup to rinse it off in after each use. I don't have a separate RODI bin.

 

[Randy Holmes-Farley Verified Community Expert]

I

I’d think you would need Hanna packets from more than just one batch. Of course packets from the same batch are likely to read the same

I think DIY solutions are the only way one can reliably calibrate any of these checkers

Yes, that's true. I've just never understood how any conductivity meter could read one 53 mS/cm solution correctly (the presumed calibration standard) and then immediately read another 53 mS/cm solution (or close to it) as lower than 53 mS/cm.

Maybe the solutions just are highly variable, or maybe they have some systematic error in manufacturing.

 

[BrightReefer]

So does this mean it’s safe to buy these now?

 

[cloudie]

I recently installed the new Redsea Reefsense salinity probe that claims to have 4 electrode tech and is more accurate that other hobby grade conductivity meter, calibrated it and noticed that my calibrated Hanna salinity checker reads almost 1.5ppt lower than redsea, opened up 2 new packets of Hanna calibration fluid and checked using the Redsea, and my Redsea consistently read 1.5ppt higher.

 

[Randy Holmes-Farley Verified Community Expert]

I recently installed the new Redsea Reefsense salinity probe that claims to have 4 electrode tech and is more accurate that other hobby grade conductivity meter, calibrated it and noticed that my calibrated Hanna salinity checker reads almost 1.5ppt lower than redsea, opened up 2 new packets of Hanna calibration fluid and checked using the Redsea, and my Redsea consistently read 1.5ppt higher.

Interesting, thanks!

What did you use to calibrate the Red Sea and can you calibrate the Hanna with that?

FWIW, I agree that 4 electrode probes can be better. I used one from Orion for 20 years.

 

[EnterName]

It's been a while since I've looked into this, but from what I remember, the Hanna tester was fine when calibrated at the right temperature (25°C/77°F).

Obviously it should calibrate correctly at different temperatures since it has a built-in thermometer to compensate, but from what I've tested, it doesn't work that way.

My guess is either their calibration code fails to apply the correct temperature compensation, or the calibration liquid differs vastly in conductivity from actual saltwater as temperature changes.

Soaking the electrodes in 1% HCl for a minute or two and then giving them a good RO/DI rinse before calibration also helped with the stability of the readings.

 

[EricR]

FWIW, I like my Hanna salinity checker calibrated with Randy's DIY conductivity standard.
I gave up on the Hanna calibration packets long ago.
*I do float the standard to match tank temperature before calibrating

Nowadays, I use TM hydrometer for tank salinity and Hanna solely for newly mixed saltwater, mainly because it's quick and easy and has ATC (and I don't worry about the temperature of my new saltwater).

 

[BeanAnimal]

I had one that I threw away along with the pocket pH tester and pocket TDS probe. None of them were reliable for me. They were the old versions. I don’t know if they have changed much or not.

 

[BeanAnimal]

I also want to follow up and say that I have purchased numerous calibrations fluids over the years from various brands. Bottles and one time use packets, usually two different brands at a time. I have always been stunned that they rarely match.

For Salinity, I think that Randy’s DIY recipes are the better alternative.

 

[jonelder68]

Mines in the trash never mattered what calibration fluid. If you calibrated it with known level fluid it would work that time but a week or even days later it’s so far off. Paper weight junk!

 

[cloudie]

Interesting, thanks!

What did you use to calibrate the Red Sea and can you calibrate the Hanna with that?

FWIW, I agree that 4 electrode probes can be better. I used one from Orion for 20 years.

I used the official 53.1 mS/cm @ 25C calibration fluid that came in the box, the probe has built in temperature sensor to auto compensate the temp during calibration.

I didn't calibrate the Hanna with it, though it should have calibrated fine.

At this point I think I'll just make a diy solution using your guide to verify the Redsea and as calibration solution for Hanna.

The Hanna is really easy to use but its reliability is questionable, threw away an old version after it refused to hold calibration for more than a few days and got the updated version with blue color probes and i hope it will last.