Hannah salinity (problems?) v. Neptune and Refractometer

[offtropic]

Hey there! I'm trying to verify my salinity and currently have access to Hannah, Neptune (via Apex) and a Refractometer. Does anyone else have issues with the Hannah instrument not matching other technologies? After repeated calibrations Hannah is reading about 2-3 points higher (39ppt) versus the Neptune (35.5ppt) and Refractometer (36ppt). I love the idea of something I can just dip in the tank or salt mix to double-check salinity but so far I am really not impressed. Having to rinse with RO and dry it each time is also a pain compared to the simplicity of the refractometer (much easier to rinse and dry). What am I missing? It doesn't appear to be as accurate and takes more maintenance so far....

How are others finding their Hannah as compared to something else they use to confirm/verify?

 

[SteveEreef]

I used the Hanna checker for about a year. While not accurate it was consistently .002 sg lower than my refractometer. Then eventually it would not stay consistent no matter how many times I would calibrate with the Hanna solution. I gave up and now use three refractometers which all read about the same. I only use the Hanna now to check temperature.

 

[gfd71]

I just use a refractometer but I only check my salinity maybe once every few weeks. I have an ato and I weigh my salt for water changes so it’s always the same

 

[SPR1968]

They all have margins of error so just pick one and stick with it.

I always used a red sea refractometer for years and then I purchased Apex and it never matched so I wouldn’t trust that. I just use it as a monitor only.

I purchased the Hanna last year and that’s what I now use as ‘the standard’ and I make apex match it by calibrating it with tank water rather than the fluid they provide..

 

[offtropic]

They all have margins of error so just pick one and stick with it.

I always used a red sea refractometer for years and then I purchased Apex and it never matched so I wouldn’t trust that. I just use it as a monitor only.

I purchased the Hanna last year and that’s what I now use as ‘the standard’ and I make apex match it by calibrating it with tank water rather than the fluid they provide..

The problem is that a 3-4ppt swing is pretty significant in a marine system - I really want to know if I'm at 35-36ppt or 39ppt. There will also be some variances in salinity in a 110 gallon system (not too much but +/- 1ppt is probably reasonable) around target numbers so that difference could even be stretched more at times. So if the Hannah is not correct and I just use it to adjust my system to 35ppt I could easily be at 32ppt (with variances down to 31ppt) and not know it.

Again, the Apex and Refractometer are both giving me similar results and the Hannah is out there quite a bit.

 

[ca1ore]

For accuracy, I rely on my calibrated refractometer. I do also use the apex probe, and have been able to get it pretty close. I mostly just serves as an alert.

 

[adrianr514]

The problem is that a 3-4ppt swing is pretty significant in a marine system - I really want to know if I'm at 35-36ppt or 39ppt. There will also be some variances in salinity in a 110 gallon system (not too much but +/- 1ppt is probably reasonable) around target numbers so that difference could even be stretched more at times. So if the Hannah is not correct and I just use it to adjust my system to 35ppt I could easily be at 32ppt (with variances down to 31ppt) and not know it.

Again, the Apex and Refractometer are both giving me similar results and the Hannah is out there quite a bit.

If the Hanna is correct it wouldn’t be considered a swing.

your Alex reads and has read ~35ppt, and if the Hanna is correct your Apex 35ppt is really 39ppt And as long as your apex stays at the 35ppt it’s stable not a swing.

A swing would be your apex reading 31ppt then next thing you know it reads 35ppt.

there’s a couple of threads out there on the Hanna Salinity Checker and it’s accuracy along with replies from Hanna. Give it a search.

 

[offtropic]

If the Hanna is correct it wouldn’t be considered a swing.

your Alex reads and has read ~35ppt, and if the Hanna is correct your Apex 35ppt is really 39ppt And as long as your apex stays at the 35ppt it’s stable not a swing.

A swing would be your apex reading 31ppt then next thing you know it reads 35ppt.

there’s a couple of threads out there on the Hanna Salinity Checker and it’s accuracy along with replies from Hanna. Give it a search.

I agree 'swing' wasn't the correct word to use - I'm concerned with its accuracy if off by 3-4 points from both the Refractometer and Apex probe. If the Hannah is correct my tank is currently at 39ppt which is borderline. If I drop my salinity so that the Hannah reads 35-36ppt then the Apex and refractometer will read around 31ppt (again, far from optimal). So, it does matter which test I choose and right now I have two calibrated tests consistent with each other and contradicting the calibrated Hannah reader.

I did a couple searches before posting but nothing really showed up. I'll look again when I get a chance.

 

[adrianr514]

I agree 'swing' wasn't the correct word to use - I'm concerned with its accuracy if off by 3-4 points from both the Refractometer and Apex probe. If the Hannah is correct my tank is currently at 39ppt which is borderline. If I drop my salinity so that the Hannah reads 35-36ppt then the Apex and refractometer will read around 31ppt (again, far from optimal). So, it does matter which test I choose and right now I have two calibrated tests consistent with each other and contradicting the calibrated Hannah reader.

I did a couple searches before posting but nothing really showed up. I'll look again when I get a chance.

Here’s the thread which also links to another thread where testing was done.

it’s also explained why conductivity is the superior form of measurement of a refractometer.

Hanna Salinity Tester - first impressions

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...

www.reef2reef.com

 

[ScottB]

My APEX conductivity probe is the least reliable. In fact right now it is reading 41ppt. I keep a swing arm hydrometer that I trust more than the APEX probe. I need to recalibrate it to my tank water, again. For like the 5th time.

My Veegee is my go to, but I do have to calibrate it now and again.

 

[dadnjesse]

I gave up on my Hanna Salinity checker a long time ago

 

[offtropic]

I gave up on my Hanna Salinity checker a long time ago

What were the reasons?

 

[offtropic]

Here’s the thread which also links to another thread where testing was done.

it’s also explained why conductivity is the superior form of measurement of a refractometer.

Hanna Salinity Tester - first impressions

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...

www.reef2reef.com

Thanks for the link. That thread linked to others...quite the rabbit hole!

Unfortunately I'm still a bit confused as to the big disparity in my readings. From what I understand, most people having issues have them with the Hanna reading lower than their refractometer. Ok...as long as that difference isn't too huge that can make sense since there might be a 'bunch of stuff' (highly scientific terminology!) that can elevate the refractometer reading (such as Mg). In my case though I am getting a reading on the Hannah significantly higher than the probe/refrac. I tested everything in both my new salt water and the tank (and tank water removed from the tank and placed in a cup) and it was the same differences each time.

If the Hanna is right then my calibration solution isn't at the correct concentration and the apex probe isn't accurate (which is certainly very possible). However, I've used two different calibration solutions (BRS and Pinpoint) for the refrac and they both match very well...

The temp part of the meter is within 0.1F of both the apex temp probe and my separate Hanna Checktemp probe (so no problem there).

Current pertinent tank numbers:
Temp - 77.3 to 77.8F
Mg - 1500 (Red Sea)
Ca - 430 (Red Sea)
Alk - 8.0 dkh (Hanna)
pH - 8.25 to 8.40

I mean, I can just keep using it and see...could split the difference as long as readings are consistent. If they were cheaper I'd order another to compare.

 

[ScottB]

Thanks for the link. That thread linked to others...quite the rabbit hole!

Unfortunately I'm still a bit confused as to the big disparity in my readings. From what I understand, most people having issues have them with the Hanna reading lower than their refractometer. Ok...as long as that difference isn't too huge that can make sense since there might be a 'bunch of stuff' (highly scientific terminology!) that can elevate the refractometer reading (such as Mg). In my case though I am getting a reading on the Hannah significantly higher than the probe/refrac. I tested everything in both my new salt water and the tank (and tank water removed from the tank and placed in a cup) and it was the same differences each time.

If the Hanna is right then my calibration solution isn't at the correct concentration and the apex probe isn't accurate (which is certainly very possible). However, I've used two different calibration solutions (BRS and Pinpoint) for the refrac and they both match very well...

The temp part of the meter is within 0.1F of both the apex temp probe and my separate Hanna Checktemp probe (so no problem there).

Current pertinent tank numbers:
Temp - 77.3 to 77.8F
Mg - 1500 (Red Sea)
Ca - 430 (Red Sea)
Alk - 8.0 dkh (Hanna)
pH - 8.25 to 8.40

I mean, I can just keep using it and see...could split the difference as long as readings are consistent. If they were cheaper I'd order another to compare.

A typical LFS will have a handful of "store use" refractometers, swing arms, etc. See what they come up with?
Consistent salinity is pretty important, so I appreciate your effort to figure this out.

 

[metzer]

My hanna goes out of calibration about every 4 to 6 weeks and i need to re-calibrate it.

 

[homer1475]

After calibration have you dunked the hanna in the solution to see of it comes out to 35ppt?

I switched to just using the hanna many months ago(might even be a year now?). While I do not use nor trust the apex probe, my hanna matches my refractometer spot on.

 

[metzer]

After calibration have you dunked the hanna in the solution to see of it comes out to 35ppt?

I switched to just using the hanna many months ago(might even be a year now?). While I do not use nor trust the apex probe, my hanna matches my refractometer spot on.

Yes, it comes out usually close. I then calibrate my apex and the two never match. Apex usually is withing 1ppt, sometimes positive, sometimes negative.

 

[homer1475]

I would not rely on the apex probe to give accurate readings. Just search some threads on here and you'll find the apex probe is not to be trusted.

"usually close" isn't very scientific lol. If after calibration you dunk it back into the calibration solution and the hanna does not report 35ppt, I would be contacting hanna for a replacement. There's a few threads around where the device would not hold a calibration, and hanna replaced those units.

 

[adrianr514]

Try this as well for the Alex probe.

 

[joec]

Get the VEEGEE STX 3 refractometer and forget about it. I had the cheaper BRS recfractometer, it sucks

I only have calibrate the VEEGEE about once every 6-8 months and it only off by a tiny amount