Hanna Salinity Tester - first impressions

[Sleepydoc]

Ok - I got back in town and had a nice little present from Marine Depot waiting for me! I've played around with it a bit and I have to say, I'm very impressed.

Like the Hanna checkers, it comes in a nice, sturdy plastic case - it's about the same size as the case for my refractometer.

4 packets of 35 ppt calibration fluid are included. It even has space to store these in the case behind the tester so you don't have random packets floating around with the rest of your fish stuff!


There was a smudge of some dirt on the inside - I read that the tester uses carbon electrodes, so I though it might be some carbon dust from manufacturing, but it didn't rinse off or rub off. Not sure what it is but it didn't seem to affect the accuracy.


Bottom view - you can see the electrodes along with the temperature sensor on the left


Calibration was simple - you rinse the unit in DI water and wipe it off, then turn the unit on, press the calibrate button and place the tester in the packet of fluid. It took about 10-15 seconds or so and that's it. Hanna recommends calibrating about once a month. Marine Depot sells 25 packets for $26 - that should last you for 2 years at $1 per month. Calibrating my refractometer isn't difficult per se - put a few drops of fluid on and adjust the screw as necessary, but I've found that it's very unpredictable when it will drift out of calibration, so I have to calibrate it every time I use it. Plus, refractometers aren't very easy to read (see below.) The Hanna Tester has this beat in spades.

To take a measurement, you dip the end in the water, far enough to submerge the probes, shake a bit to make sure bubbles are removed and wait for the reading to stabilize. It took between 10-12 seconds in my testing. The readings were very repeatable - I took 4 readings in my tank and they were all either 35.0 or 35.1 ppt. Comparing to my vertex refractometer, the readings were dead on. At least I think they were - the consistent problem I have with the refractometer is it's really hard to get more than 0.5 ppt accuracy, and the crispness of the line really depends on the light you use to view. No such problems with the Hanna Tester - LCD displays rock! I don't have a Milwaukee or other digital testers to compare against.

Afterwards, you rinse with some DI water, wipe it dry and you're set.

For the record, I also verified that it floats, just like Hanna says it will - strong work, Hanna!

It's powered by a CR2032 battery and the display gives you the battery percentage on startup. This is a really common battery size, so they're not hard to find, but most of us don't have them laying around, so knowing in advance that the battery is starting to go is quite convenient.

Overall, I'm very impressed and pleased with this tester. In my initial testing it's easy to use, reliable and repeatable. Unless something changes, my trusty refractometer will be gathering a lot of dust. At $70, it's very reasonably priced and I can't see spending $35-40 on a refractometer when you can have this for not that much more. I'll check back with an update when I've had more experience, but kudos to @Hanna Instruments for what seems to be a great product!

 

[Schweezy]

Thank you for the great review.

 

[Sleepydoc]

Just noticed @wangspeed posted some of his results comparing the Hanna with other units and had similar conclusions re: accuracy.

 

[Retro Reefer]

I’m still trying to convince myself mine is right I have been using a refractometer and a old hydrometer for years and they both read almost identical however the Hanna is showing that my salinity is 2 ppt lower than I had thought. I Calibrated the Hanna before use and after the large discrepancy I weighed up some salt and carefully measured water to make up my own calibration solution to 1.022 SG and the Hanna is showing 1.021 SG. Mine also had the black smudges on the probes

 

[tatties]

i have this and love it, trust more than the refractormeter

 

[lakai]

Cal button should have been swapped with the button by the battery imo. It is .002 sg lower from my milwaukee.

 

[Hanna Instruments]

Ok - I got back in town and had a nice little present from Marine Depot waiting for me! I've played around with it a bit and I have to say, I'm very impressed.

Like the Hanna checkers, it comes in a nice, sturdy plastic case - it's about the same size as the case for my refractometer.

4 packets of 35 ppt calibration fluid are included. It even has space to store these in the case behind the tester so you don't have random packets floating around with the rest of your fish stuff!


There was a smudge of some dirt on the inside - I read that the tester uses carbon electrodes, so I though it might be some carbon dust from manufacturing, but it didn't rinse off or rub off. Not sure what it is but it didn't seem to affect the accuracy.


Bottom view - you can see the electrodes along with the temperature sensor on the left


Calibration was simple - you rinse the unit in DI water and wipe it off, then turn the unit on, press the calibrate button and place the tester in the packet of fluid. It took about 10-15 seconds or so and that's it. Hanna recommends calibrating about once a month. Marine Depot sells 25 packets for $26 - that should last you for 2 years at $1 per month. Calibrating my refractometer isn't difficult per se - put a few drops of fluid on and adjust the screw as necessary, but I've found that it's very unpredictable when it will drift out of calibration, so I have to calibrate it every time I use it. Plus, refractometers aren't very easy to read (see below.) The Hanna Tester has this beat in spades.

To take a measurement, you dip the end in the water, far enough to submerge the probes, shake a bit to make sure bubbles are removed and wait for the reading to stabilize. It took between 10-12 seconds in my testing. The readings were very repeatable - I took 4 readings in my tank and they were all either 35.0 or 35.1 ppt. Comparing to my vertex refractometer, the readings were dead on. At least I think they were - the consistent problem I have with the refractometer is it's really hard to get more than 0.5 ppt accuracy, and the crispness of the line really depends on the light you use to view. No such problems with the Hanna Tester - LCD displays rock! I don't have a Milwaukee or other digital testers to compare against.

Afterwards, you rinse with some DI water, wipe it dry and you're set.

For the record, I also verified that it floats, just like Hanna says it will - strong work, Hanna!

It's powered by a CR2032 battery and the display gives you the battery percentage on startup. This is a really common battery size, so they're not hard to find, but most of us don't have them laying around, so knowing in advance that the battery is starting to go is quite convenient.

Overall, I'm very impressed and pleased with this tester. In my initial testing it's easy to use, reliable and repeatable. Unless something changes, my trusty refractometer will be gathering a lot of dust. At $70, it's very reasonably priced and I can't see spending $35-40 on a refractometer when you can have this for not that much more. I'll check back with an update when I've had more experience, but kudos to @Hanna Instruments for what seems to be a great product!

Cal button should have been swapped with the button by the battery imo. It is .002 sg lower from my milwaukee.

I’m still trying to convince myself mine is right I have been using a refractometer and a old hydrometer for years and they both read almost identical however the Hanna is showing that my salinity is 2 ppt lower than I had thought. I Calibrated the Hanna before use and after the large discrepancy I weighed up some salt and carefully measured water to make up my own calibration solution to 1.022 SG and the Hanna is showing 1.021 SG. Mine also had the black smudges on the probes

Thanks for the feedback everyone, we strive to provide the best testing experience possible. Our HI98319 waterproof salinity and temperature tester has an accuracy statement of ±0.001 S.G. (@ 25°C/77°F). The MA887 Digital Refractometer for Seawater Measurements has an accuracy statement of ±0.002 S.G.

What is refractometry?

With our HI96822 salinity determinations are made by measuring the refractive index of seawater. Refractive Index is an optical characteristic of a substance and the number of dissolved particles in it. Refractive Index is defined as the ratio of the speed of light in empty space to the speed of light in the substance. A result of this property is that light will “bend”, or change direction, when it travels through a substance of different refractive index.

What is conductivity?

Conductivity is most commonly defined as a substance’s ability to transmit heat, sound, or electricity. Small charged particles called ions help to carry the electrical charge through a substance. These ions can be positively or negatively charged. The more ions available the higher the conductivity; fewer ions will result in lower conductivity. Also, the higher the conductivity, the higher a solution’s ability to conduct electricity. This is a result of a large number of charged ions present in the solution. Since the various elements used to make up salinity carry an ionic charge, conductivity is used to determine their gross concentration in water.

What is better for salinity?

When comparing conductivity to refractometery to measure salinity, the consensus among the scientific community favors conductivity. This is because there are non-conductive material which can impact the refractive index of seawater but not the actual salt concentration. For example, if we add sugar to artificial seawater, we will see that our salinity value will increase but we have not changed the concentration of salt in the water. If we measured the salinity of that sample with our HI98319 conductivity meter you’ll notice the value is largely unchanged. It is common to have inflated values with a refractometer due to the large number of materials which will affect the density of that water outside of the dissolved salt values. For example, organic waste, sugars, potential non-ionic contaminants or uneaten fish food can increase the values produced on a refractometer but this would be less likely to occur on a conductivity meter like the HI98319.

Important Information about our HI98319

1. You cannot use the calibration solution for refractometers. The calibration solution is a 35ppt conductivity standard based off of the International Oceanographic Tables
2. The calibration solution is a one time use and cannot be reused after calibration
3. The black residue is nothing to be worried about, it happens when we polish the graphite electrodes before shipping. It will eventually come off but it will not affect the readings. You can wipe it off with cloth or cardboard.

 

[Sleepydoc]

I’m still trying to convince myself mine is right I have been using a refractometer and a old hydrometer for years and they both read almost identical however the Hanna is showing that my salinity is 2 ppt lower than I had thought. I Calibrated the Hanna before use and after the large discrepancy I weighed up some salt and carefully measured water to make up my own calibration solution to 1.022 SG and the Hanna is showing 1.021 SG. Mine also had the black smudges on the probes

I think the calibration needs to be 35 ppt (1.026 SG) Also, I'm not sure if making a calibration solution like that will work with a conductivity tester like the Hanna. (not saying it won't, either - you'd have to check with Hanna.) What you really need is either a known reference solution or a gold standard measurement device - as it is it could be that either the Hanna is off or your refractometer is off.

The other question is how consistent are the readings from the Hanna Tester (or your refractometer) As a practical matter, a difference 0f 0.001 SG is not really significant. The consistency matters more. If your tank were consistently 1.025 rather than 1.026, your livestock would still be fine.

Cal button should have been swapped with the button by the battery imo. It is .002 sg lower from my milwaukee.

I have no experience, but @wangspeed mentioned in his thread that his Milwaukee was consistently off by 0.002.

 

[dante411x]

Thanks for the review! I’ve been considering something better than the trusty old refractometer..

Kind of debating this. I’m about to pick up the apex. That comes with a conductivity probe. But it has some.. interesting reviews in the whole “accuracy” department. Would be nice to have a separate conductivity test I could do to check on it from time to time. And it’s not like I can drag that probe from the tank to the new water every time I mix it.

 

[Retro Reefer]

I think the calibration needs to be 35 ppt (1.026 SG) Also, I'm not sure if making a calibration solution like that will work with a conductivity tester like the Hanna. (not saying it won't, either - you'd have to check with Hanna.) What you really need is either a known reference solution or a gold standard measurement device - as it is it could be that either the Hanna is off or your refractometer is off.

I calibrated the Hanna with the included 35ppt solution when I set it up out of the box but because of the large difference between my other testers I decided to make up my own saltwater to a known value using IO’s formula of 2.4 oz salt mix combined with 16 oz water to produce 1.022 SG water at 77 deg.. I’m assuming the sample of water I made was fairly accurate as I carefully measured water and used a lab grade scale to weight salt. The Hanna indicated 1.021 SG in the batch I made so that’s within error.. I halfway made my post tongue in cheek as I’m just having a hard time believing both my other testers where off almost exactly 2 ppt each but I’m assuming the Hanna must be right. I will note the refractometer had been calibrated to 0 using distilled water which I know is not the preferred method but because readings matched my old hydrometer I assumed it was fairly accurate.

 

[Retro Reefer]

The other question is how consistent are the readings from the Hanna Tester (or your refractometer) As a practical matter, a difference 0f 0.001 SG is not really significant. The consistency matters more. If your tank were consistently 1.025 rather than 1.026, your livestock would still be fine.

Consistently is not the issue for me it’s chemistry and explains why my Mg and other elements have consistently run low on my tanks, bringing everything up 2 ppt should make a big difference.

 

[hotashes]

Excuse my ignorance here, although I’ve been using the Milwaukee MA887, aren’t all hobby grade salinity instruments accurate up to +-.2%? If so does that imply unless lab grade all readers will have slight variation within 2 ppt?

A.

 

[dante411x]

I calibrated the Hanna with the included 35ppt solution when I set it up out of the box but because of the large difference between my other testers I decided to make up my own saltwater to a known value using IO’s formula of 2.4 oz salt mix combined with 16 oz water to produce 1.022 SG water at 77 deg.. I’m assuming the sample of water I made was fairly accurate as I carefully measured water and used a lab grade scale to weight salt. The Hanna indicated 1.021 SG in the batch I made so that’s within error.. I halfway made my post tongue in cheek as I’m just having a hard time believing both my other testers where off almost exactly 2 ppt each but I’m assuming the Hanna must be right. I will note the refractometer had been calibrated to 0 using distilled water which I know is not the preferred method but because readings matched my old hydrometer I assumed it was fairly accurate.

I’m not sure if this applies to the Hanna checker, but I know the apex conductivity probe can’t be calibrated with saltwater. It uses the microsiemens calibration solution. Since this is also a conductivity meter, wouldn’t it have similar issues with being calibrated with salt water instead. Considering that it’s extrapolating the salinity of water from a conductivity test.

 

[Butuz]

Mine is way off. Both (fully recalibrated) BRS refractometer and digital controller probe show 1.025 (where its been since day 1), I have used 3 packets of Hanna recalibration liquid and it still reads 1.022. I tried both in the tank and a new mix for watrer changes, same result. It is consistent, but inaccurately consistent. I will call Hanna tomorrow to exchange for a non defective one.

 

[litenyaup]

Thanks for all the reviews as i was wondering about this unit. Great info!

 

[Sleepydoc]

@Retro Reefer - Hanna has a nice explanation in their post about the difference between refractometry vs conductance for measuring salinity; this also explains why one should generally use a calibration solution designed for the probe you're calibrating. Ultimately, both methods are indirectly measuring salinity and extrapolating. An excess of other conductive ions relative to Na & Cl could skew the results of a conductivity probe, and anything that alters the refractive index will skew the results of a refractometer.

Are you mixing your salt to 1.022 or 1.026? 1.026 SG/35 ppt is generally considered 'standard' for see water, so if you're mixing lower, that could explain why your parameters are running low as well. Generally, 35 ppt is corresponds to 1.026 SG, so I'm not sure how it would have worked to calibrate the tester with salt mixed to 1.022.

@hotashes - 'hobby grade' equipment spans a wide range of quality (something we can all attest to!) Each manufacturer will or should publish the specs for accuracy for their equipment. The instructions that came with my tester list the accuracy ± 1.0 ppt or ± 0.001 SG and ±0.5º C/± 1º F. Milwaukee lists the accuracy of their digital refractometer as ±2 ppt/± 0.002 SG. Likewise, there is no standard that makes something 'lab grade.' It's just a label applied by people to market equipment. Anything truly 'lab grade' will have published specs regarding its accuracy. If you work in a lab, you buy equipment according to your needs. If you want higher accuracy, you pay for better equipment to get it. If you're in a lab that's keeping fish, the accuracy of many 'hobby grade' refractometers may be perfectly fine.

The apex conductivity probe has been notoriously fickle and prone to false readings caused by stray currents, micro bubbles, etc. It's also not temperature compensated (at least not very well.) mine shows definite variation with temperature. I use mine for gross measurements and following trends only; if I want to know the actual salinity I use a refractometer and now the Hanna tester.

 

[Retro Reefer]

Hanna has a nice explanation in their post about the difference between refractometry vs conductance for measuring salinity; this also explains why one should generally use a calibration solution designed for the probe you're calibrating. Ultimately, both methods are indirectly measuring salinity and extrapolating. An excess of other conductive ions relative to Na & Cl could skew the results of a conductivity probe, and anything that alters the refractive index will skew the results of a refractometer.

Are you mixing your salt to 1.022 or 1.026? 1.026 SG/35 ppt is generally considered 'standard' for see water, so if you're mixing lower, that could explain why your parameters are running low as well. Generally, 35 ppt is corresponds to 1.026 SG, so I'm not sure how it would have worked to calibrate the tester with salt mixed to 1.022.

I never said I was calibrating my Hanna with the water I made.. The water was made to a known standard to produce 1.022 SG which I used to check/verify the Hanna’s readings, NOT to calibrate it. Been reefing 35 years, I know SG standards and the ramifications of having low specific gravity.

 

[Butuz]

@Retro Reefer - Hanna has a nice explanation in their post about the difference between refractometry vs conductance for measuring salinity; this also explains why one should generally use a calibration solution designed for the probe you're calibrating. Ultimately, both methods are indirectly measuring salinity and extrapolating. An excess of other conductive ions relative to Na & Cl could skew the results of a conductivity probe, and anything that alters the refractive index will skew the results of a refractometer.

Are you mixing your salt to 1.022 or 1.026? 1.026 SG/35 ppt is generally considered 'standard' for see water, so if you're mixing lower, that could explain why your parameters are running low as well. Generally, 35 ppt is corresponds to 1.026 SG, so I'm not sure how it would have worked to calibrate the tester with salt mixed to 1.022.

@hotashes - 'hobby grade' equipment spans a wide range of quality (something we can all attest to!) Each manufacturer will or should publish the specs for accuracy for their equipment. The instructions that came with my tester list the accuracy ± 1.0 ppt or ± 0.001 SG and ±0.5º C/± 1º F. Milwaukee lists the accuracy of their digital refractometer as ±2 ppt/± 0.002 SG. Likewise, there is no standard that makes something 'lab grade.' It's just a label applied by people to market equipment. Anything truly 'lab grade' will have published specs regarding its accuracy. If you work in a lab, you buy equipment according to your needs. If you want higher accuracy, you pay for better equipment to get it. If you're in a lab that's keeping fish, the accuracy of many 'hobby grade' refractometers may be perfectly fine.

The apex conductivity probe has been notoriously fickle and prone to false readings caused by stray currents, micro bubbles, etc. It's also not temperature compensated (at least not very well.) mine shows definite variation with temperature. I use mine for gross measurements and following trends only; if I want to know the actual salinity I use a refractometer and now the Hanna tester.

I mix my salt to 1.025 and have had it at that level since day 1. The science behind it is irrelevant in my opinion. I bought a probe expecting to stick it into the tank or freshly mixed water and expect an accurate salinity level check. If my LFS, BRS refractometer and ekoral probe are all showing 1.025 and Hanna is showing 1.022, then I dont need a scientific article on which one is not working properly. I don’t care re the science behind it or their breakthrough connectivity technology etc - they are irrelevant, they can use dark magic to give me accurate readings and I’d be happy with that. Today, if I mix my salt to 1.025 according to Hanna’s probe, I will probably end up with actual salinity closer to 1.03, which I suspect may not work out well for my tank inhabitants.

 

[Sleepydoc]

I never said I was calibrating my Hanna with the water I made.. The water was made to a known standard to produce 1.022 SG which I used to check/verify the Hanna’s readings, NOT to calibrate it. Been reefing 35 years, I know SG standards and the ramifications of having low specific gravity.

Ah, ok. From your post it sounded like you mixed some salt water to 1.022 and used that to calibrate the tester. I was trying to figure out how that worked!

 

[Butuz]

Ah, ok. From your post it sounded like you mixed some salt water to 1.022 and used that to calibrate the tester. I was trying to figure out how that worked!

No worries at all. I spoke to Hanna, great customer service. I will exchange this one and hoping this is simply a unit defect as I like the probe, its simplicity and design +temp all in one. Hopefully, the replacement one will work fine.