Salinity - Refractometer vs Hannah

[MattPG]

New reefer - Started out using a refractometer. I wear glasses and always had some difficulty reading the result even with the little LED. So, if you have trouble reading it then you can't be confident doing the calibration either. So, I did my best but still uncomfortable and wanted a more accurate solution. Bought the Hanna hand held salinity tester HI98319. Self calibrating and easy to use. Only problem is it gives me results that are always 3-4ppt different (lower) than the refractometer result which I have run side by side. I am inclined to just trust the Hanna but wanted to hear others advice. Thanks!

 

[blaxsun]

I had the Hanna but always found the results were off as well. I ended up just switching to a standard refractometer and haven't looked back. My LFS has an expensive refractometer and I'll occasionally take a water sample in to see what theirs tests as - then recalibrate mine as needed.

 

[KStatefan]

Just did water test on my tanks

Display Tank
Hanna 1.024
Tropic Marin Hydrometer 1.0249 corrected for temp 1.0246

QT tank
Hanna 1.026
Tropic Marin Hydrometer 1.0268 corrected for temp 1.0266

 

[Randy Holmes-Farley Verified Community Expert]

I had the Hanna but always found the results were off as well. I ended up just switching to a standard refractometer and haven't looked back. My LFS has an expensive refractometer and I'll occasionally take a water sample in to see what theirs tests as - then recalibrate mine as needed.

You are assuming the LFS is correct just because it's an expensive refractometer? Maybe they've never even calibrated it. lol

 

[EricR]

FWIW, I just got the Tropic Marin Precision Hydrometer a few days ago -- dang that thing is big!

Test just now in tank at 77d F:
- Tropic Marin = 1.0255 ...barely enough room in 40 breeder to do in tank testing but works (with all flow OFF)
- 2 OLD swing arm hydrometers = visually pretty much spot on with the TM
- Hanna digital = 1.025

...so feeling good enough about the salinity testers I have on hand right now -- I really only ever test during water changes, for the most part.

 

[Rando]

A conductance meter (Hanna) and a standard refractometer cannot show the same results. I only rely on Hanna's salinity tester..it's quite accurate

I also have an Aqua Medic refractometer and it always shows me 2-3 ppt too much compared to the Hanna salinity tester. And the last ICP agrees with Hanna.

 

[Rmckoy]

Choose one and trust it .
find a calibration solution for it .
switching from one to another can give varying results

 

[dmsc2fs]

Choose one and trust it .
find a calibration solution for it .
switching from one to another can give varying results

Buy a Tropic Marin Floating Hydrometer
Pick a Refractometer
Calibrate Refractometer to Hydrometer
Trust it

*Hydrometer is overly cumbersome for daily use.

 

[Randy Holmes-Farley Verified Community Expert]

A conductance meter (Hanna) and a standard refractometer cannot show the same results. I only rely on Hanna's salinity tester..it's quite accurate

I also have an Aqua Medic refractometer and it always shows me 2-3 ppt too much compared to the Hanna salinity tester. And the last ICP agrees with Hanna.

What do you mean they cannot? You mean you have two that do not show the same?

Conductivity, refractive index, and specific gravity (hydrometer) devices will show the same when properly manufactured and calibrated.

 

[jda]

A man with two refractometers never knows what time it is. Wait, was that how it goes?

In any case. Hold the refractometer up to a real light or near a window. It should make it much easier to see the blue and the while.

 

[EricR]

I know I'm in the minority but, personally, the swing arm hydrometers are fastest and easiest for me.
All 3 of my old ones visually match my Tropic Marin Precision Hydrometer that I trust,,, but it's way too much of a pain to use for normal testing -- so it's just my periodic reference against my other devices.

Hanna digital EC salinity meter works well for me also but I find I spend more time being careful to clean it after so, in the end, takes more time than the swing arms for quick checks.

 

[LeftyReefer]

When using a refractometer, I found it always helped to look through it, into a really really bright light.

I use a rechargeable hand-held LED light for use around (under) my tanks and such and for use while reading test results... I place it head level and look directly into it using my refractometer. Brightens it up nicely and have no trouble reading it. If you can't read your refractometer, try a brighter light behind it.

Saying that, I love my Hanna hand held salinity checker. LOVE LOVE LOVE it. would not go back.

 

[EricR]

When using a refractometer, I found it always helped to look through it, into a really really bright light.

I use a rechargeable hand-held LED light for use around (under) my tanks and such and for use while reading test results... I place it head level and look directly into it using my refractometer. Brightens it up nicely and have no trouble reading it. If you can't read your refractometer, try a brighter light behind it.

Saying that, I love my Hanna hand held salinity checker. LOVE LOVE LOVE it. would not go back.

I can't even fathom how visual refractometers have been the staple for so long.
Not my cup of tea. (((Just personal note)))

 

[GillMeister]

I will never, ever, use a hydrometer again. I had carried one over from my old system and found that it was off about .005 SG. Got a refractometer, started reading salinity rather than SG and totally trust the results. Other than trying to read the results being a task for younger eyes I don't think I would trust a Hanna checker as much.

 

[homer1475]

Hanna all the way....

Used a hydrometer for years before we knew any better. Switched ot a refractometer for many years, then when the Hanna came out, switched to it.

In the 3 years I've had mine, I've calibrated it every few months. Well not exactly calibrate, but check against a known standard(Hanna calibration packets), and it's always 35ppt. I haven't actually calibrated it in all of those 3 years.

My hanna matches a properly calibrated refractometer, and it's way easier to use. Besides Randy has stated many times over that conductivity is the most scientific, and accurate way to measure salinity.

 

[Jake4727]

A conductance meter (Hanna) and a standard refractometer cannot show the same results. I only rely on Hanna's salinity tester..it's quite accurate

I also have an Aqua Medic refractometer and it always shows me 2-3 ppt too much compared to the Hanna salinity tester. And the last ICP agrees with Hanna.

Sheesh be carful, I have over 4000 dollars worth of stuff almost die because my Hanna was saying 1.029 was 1.025. Till I bought a refractometer I had no clue why my levels were so elevated. I calibrated ever other use which is excessive too.

 

[Jake4727]

Invest in a good refractometer, and digital. I test in conjunction with each other and it has benefited me a lot. Salinity is the number 1 most important think so you should definitely invest and have good supply’s to test that.

 

[Randy Holmes-Farley Verified Community Expert]

Got a refractometer, started reading salinity rather than SG and totally trust the results. Other than trying to read the results being a task for younger eyes I don't think I would trust a Hanna checker as much.

Just to clarify, you went from measuring specific gravity to measuring refractive index. All types of devices that reefers use can report in units of salinity, but none of them directly measure salinity.

Drying and weighing is the only direct way and measuring all ion concentrations and adding them up (by ICP) might be considered close to direct salinity determination.

 

[Randy Holmes-Farley Verified Community Expert]

Sheesh be carful, I have over 4000 dollars worth of stuff almost die because my Hanna was saying 1.029 was 1.025. Till I bought a refractometer I had no clue why my levels were so elevated. I calibrated ever other use which is excessive too.

Was the calibration solution off?

 

[Big Smelly fish]

I use an old Milwaukee refractor for the past 15 years, it’s accurate and holds calibration well, I don’t trust the swings arm hydrometers because I have a bunch and they are all off. I calibrate them to my refractor so I can do quick checks when preparing fresh saltwater. Then use the refractor to make sure it where I want.