Hanna Salinity Tester - first impressions

JS_racer

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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.
Any update here? Mine seems low as well. Calibrated a few times, reads 32 or 33 ppt, should be 35ppt. On top of that, the cal solution seems not to be consistent. Calibration clean, rinse in ro/di recheck cal and its easily another 1.5 ppt or more off. Not sure whats going on here.
Temp is off 1 degre, i think.
 

duffer

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So my first one I got from my local lfs was reading low also. I brought it back to the store for them to check it out and it was off based on their Milwaukee tester. They gave me a new one and made sure it was calibrated and this one is spot on.
 
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Sleepydoc

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After a month and a half I’m still totally satisfied with mine. I’ve been doing readings with both the Hanna meter and with my refractometer, calibrating the refractometer every time I use it. The two either read exactly the same or the Hanna meter reads .001 lower (i.e. 1.025 instead of 1.026.) That’s within the stated accuracy of the meter, but quite honestly, that’s also the range of error for me peering into my refractometer, too.

I noticed it was reading a bit off a couple of weeks ago, so I re-calibrated it and it was spot on again after that. It could have been due to drift in the instrument but I had also inadvertently put it in calibration mode once shortly before that. I tried to cancel it but that may have thrown the calibration off, too. You do need to make sure it has time to stabilize in the tank (I assume it uses temperature to correct it’s reading so if the thermometer has not equilabrated the reading may be off.) The temperature has been accurate every time I use it,

The only time there was a significant difference between the two was one time when I tested my tank and the Hanna meter read 1.026 and my refractomter read 1.030. I wiped off the refractometer and tried it again and it read 1.026, so I have no idea why the reading was off.

Any update here? Mine seems low as well. Calibrated a few times, reads 32 or 33 ppt, should be 35ppt. On top of that, the cal solution seems not to be consistent. Calibration clean, rinse in ro/di recheck cal and its easily another 1.5 ppt or more off. Not sure whats going on here.
Temp is off 1 degre, i think.
When you calibrate it, does it read 35 ppt in the calibration solution?
 
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JS_racer

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When i calibrate it, usualy does not read 35 in the cal fluid. I hit the cal, let it do its thing, it thrn shows 35ppt. then rinse, dry, rodi, dry again. Recheck the cal packet, and its off 1 or 2 ppt.

Tanks are lower reading as well.
 

JS_racer

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Brs was great when i called, should have a new one in my hands tomorrow. Should be interesting, hope it works better. If still low, might take both and drive over there to see what i can find. They are local, and i think would also be interested to figure it out

I have hope though
 
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JS_racer

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well, the new one read about the same, i also ordered calibration drops for my refractometer, to make sure that was right on.
i decided after a couple calls to BRS to send them back, here is the exchange and what they have told me about it. Mind you on the phone, they advised i send them back , i did calibrate them to my tank water, then they read as expected, but low with the calibration solution.

BRS .......Thanks for reaching out to us. Our testing results from yesterday stated the HI98319 Marine Salinity Tester was not defective and we were able to calibrate to the standard and test tank water accurately. For our next steps we can either send it back, if not issue you a refund minus 10% for the restocking fee. If you have any further questions please let us know. Hope to hear from you soon!

Me........Hmm, strange. Reading ppt?? Or something else? At what temp was the calibration fluid?? I called a few times trying to resolve why the temp and the calibration read low. And why I was unable to calibrate it and re read the calibration fluid at 35 again. I purchased some of your 35pt refractometer solution to verify my refractometer was at 35, then tested the tank at 35. I would calibrate the new meter, then test the tank it read 32, if I were to calibrate it in the 35ppt tank, then it read the second tank as expected in comparison to the refractometer. If I calibrated it in the included packets it read both tanks low. When I called I was told to send them back, no problem.
What am I missing here??

BRS.......The product is really only intended for testing fresh mixed saltwater and not for testing tank water due to contaminates can interfere with the reading. Along with that if you don't let it settle you can get inaccurate results and ambient room temperature is recommended for the fluid. If you have any further questions please let us know.

what ??? sounds like my best bet is to pay the restocking fee and be done. I don't buy for a second these are only intended for new water, that would indicate that i need a different device to check tank water ?? Makes me wonder if it was calibrated by them at all, or if they just went off my tank calibration and dunked it in and said it was good. Room Temp, my room might be 65, another might be 80, easy to see the meter reads different at different temperatures. I had a seperate thermometer in the water in a cup floating the calibration packet, to bring to different temperatures.. the ppt was definitely different.
i wanted to like this, thats why they sent out a second one. i guess 10% to be done is a price i am willing to pay. Part of me wants to drive up there with my refractometer, and watch them calibrate, test, and then compare to my calibrated with their solution refractometer. The refractometer drops were purchased the same time as the 2nd meter was sent.
 
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Sleepydoc

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Strange. Temperature shouldn’t matter - that’s why the meter has a temp probe as well, so the meter can adjust the reading based on temperature. I’m pretty sure that’s why you see the reading vary a bit when you first put it in the tank; it’s adjusting as the temperature probe stabilizes. There’s a little hourglass on the meter display that disappears when the temp has stabilized. IME the reading doesn’t change after the first couple of seconds, though.

The specified accuracy of the meter is ±1 ppt, so calibrating at 35 ppt and getting 34 or 36 the next time would be within spec (for reference, the Milwaukee digital refractometer is spec’d at ±2 ppt.) More than that would be out of spec.

I’ve been using mine in both freshly mixed salt water as well as tank water and it’s been very consistent and accurate. Somewhere someone posted a nice explaination of the difference between readings of a conductivity probe and a refractometer. They both use a reading to estimate the salinity and both can be affected by different factors. The fact that your tank was consistently lower by the same amount and that it read properly when you used the tank to calibrate it makes me wonder if there is something in your tank that may be affecting the conductivity?

I’m happy with mine, but given your experience, I would probably eat the restocking fee, too. At least $7 isn’t the end of the world.

As an aside, it’s a good idea to calibrate a refractometer on a regular basis as they can get out of whack. I’ve taken to calibrating mine with each use because I can’t predict when it will wander.
 

JS_racer

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yep, i waited with the hourglass, not sure what the deal was.
for sure it is designed to test a tank, thats crazy to say it wouldn't be.
 

JS_racer

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well, BRS charged me $15 to return the meter that was reading low.
at least it's done, guess i have to shop around on my next purchases.
 

clockman

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I too am disappointed with my Hanna. I have been using my Milwaukee digital refractometer which matches my trusted VeeGee. Hanna gives a consistently 0.002-0.003 SG lower reading than the Milwaukee and VeeGee, 1.025 vs 1.028. I will have to retire the Hanna, if it is only good for freshly mixed saltwater and not tank water like BRS suggests. A pity.
 
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Stigigemla

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I believe the problem is that all reference solutions does not fit all purposes.

For refractometers a 3,65% sodium chloride solution measures 3,5% salinity of sea water.
For hydrometers You should have 3,714%
For conductivity meters it is 3,29% sodium chloride that responds to 3,5% salt water.

More to read here: http://reefkeeping.com/issues/2004-06/rhf/index.htm
 
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Sleepydoc

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I just used mine again to check my mixed salt water. I hadn't calibrated it in about 2 ½ months, so I calibrated it and checked again and it had drifted up 1 ppm. I then compared it to my refractometer and it read within 1 ppm for both my fresh mixed salt water and my tank water.

As an interesting side note, I actually had to calibrate my refractometer twice. I calibrated it, then checked the water which was 4-5 ppm lower than I expected, so I checked it again with the calibration fluid and sure enough it was reading low I had to adjust it again.

I just looked it up again on BRS's web site as well as Hanna's and nowhere does it say not to use it in an aquarium. In fact, the instructions say "designed for the measurement of salinity in salt water aquariums, aquaculture, brackish water or other salt water bodies," and the video put out by Hanna show it being used in an aquarium.

Mine seems to work just fine in my aquarium. I've compared it to my refractometer numerous times and never had a significant discrepancy. Since the Hanna salinity tester actually estimates the salinity from the conductivity, I wonder if there may be something specific to the water that disproportionately affects the conductivity, or affects how conductivity is read with the carbon electrodes?

For me, as a practical matter I virtually never worry about the salinity in my tank anyway. Evaporation is replaced with the ATO, so the only net loss of salt from the system is via the skimmer. The only way for the salinity to change significantly is if there is a rapid addition of DI water from the ATO and I would notice that anyway. The main time I need to check salinity is with my mixed saltwater, and the Hanna works perfectly for that.
 

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I just bought a Hanna and I too have a problem with it reading low. The Hanna appears to be reading about 2ppm lower than the BRS calibrated refractometer. I calibrated both and now have no idea which one is right or wrong. I am assuming that the refractometer is right and that the Hanna is ready low, but that's unfortunate that I spent that money on it. I was hoping to make it easy and appears to be inaccurate
 
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Hi All. Cool thread. And one of the many rabbit holes I've gone down in my 1 year of reefing so far....lol
In all the reading that I have done on measuring salinity the biggest factor is not what value you get with your measuring device, it is how consistent is it reading. Most fish really don't care if the water is 35ppt or 31ppt. Just that it doesn't swing too much.

The most common methods to measure salinity are the refractometer and conductivity probe. And neither are 100% accurate due to many variations within each sample. For either device if you want to get the most accurate reading, your water parameters must match those of the calibration fluids. Which means that if your calcium, alkalinity, or magnesium deviate from standard sea water you could get an unexpected reading. Large differences in the concentration of the major elements will affect the tools we use to measure salinity, both the refractive index and conductivity. Interesting huh? I found that to be fascinating personally.

For me I have a Hanna salinity/temperature tester and a refractometer. I use the Two Little Fishies calibration fluid for the refractometer as it is created to be standard sea water with the appropriate concentrations of the major elements. Side by side comparisons are about as close as you can get with either tool. I (try to) run my tank at 34ppt, 420 calcium, 1350 mag, and 8.5 alk. My refractometer reads basically 34ppt (at least I think it does as it is really hard to see the fuzzy blue line amongst the black lines...hence the reason I got a digital device :)) And my Hanna device reads 34.3ppt. Good enough for me.

Hope this helps some folks understand why the devices might be reading different values. Of course there are the margin of errors for the tools as well to be taken into account.

Happy Reefing!
 

Stigigemla

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@jbilliel Most calibration fluids are made for refractometer or conductive meter.
It can differ a lot between the results so you have to use a refractometer calibration fluid for the refractometer and a conductivity calibration fluid for the Hanna.
A refractometer solution can be 3,65 grams sodiun chloride with water to totally 100 grams.
A conductivity solution can be 3,29 grams sodium chloride with water to totally 100 grams.
You can read more here: http://reefkeeping.com/issues/2004-06/rhf/index.htm
 
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jbilliel

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Thanks Stigigemla - I am using solution that is made specifically for each.

I am going to try putting the Hanna conductivity solution in the water so that way the temperatures are the same. Perhaps that is not helping the situation out and creating some of the drift.
 

jbilliel

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I just calibrated both again. The refractometer shows a salinity of 35-36. The Hanna was recalibrated with hanna calibration fluid that was brought up to temp in my tank. The Hanna is showing a salinity of 33.4-33.8.

<shrug>
 

Dub

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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.
just wondering about several posts that mixed up solutions to a specific SP. Imay have read the posts wrong but I think they used salt of specific weight mixed with a prescribed volume volume of DI water. My question is was the salt properly dried before being weighed And was the temperature of the resulting solution considered? I know that salt absorbs moisture out of the air thus adding to its weight and that would make for a weaker solution. This wouldn’t affect a comparison of various instruments as they should all read the same regardless of the resulting SP, but if one mixes for a specific SP the resulting mixture would be weaker based upon how much moisture the salt had absorbed.
 

Stigigemla

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Thats why the calbration fluids above are made with sodium chloride that doesnt take up water from air of "normal" humidity.
 

jbilliel

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I was playing around with this again today and they are still about 2 ppt different from each other with the refractometer reading higher. Do I trust the refractometer more than the Hanna?
 

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