What salinity tester don I trust?? Both calibrated, both with diferent numbers…

[daniel_mourra]

Hello

I just calibrated my refractometer with brightwell refractometer calibration standard as per the instructions to 1.026 SG (35%) and my Hanna Salinity chequer using the Hanna Salinity Calibration satchet g1.026 (35%)..

When i test my aquarium water…. my refractometer displays 1.028…. Hanna says 1.025
Which do i believe??? Both are calibrated 4 minutes ago….

 

[jimk60]

Which one to trust is anyone's guess. I didn't have any luck with the hanna tester. Get a glass floating hydrometer and go with that . I use and recommend the Tropic Marin one.

 

[Muffin87]

Take a look inside your refractometer, where you take the reading, and see whether the temperature compensation is for 20C or 25C.
If doesn’t say that, take a look at the manual.

If you can’t find any information about temperature compensation, I probably wouldn’t keep using that refractometer.
Some of the cheaper refractometers sold for aquarium keeping compensate for the wrong temperature.

Take a look at the reviews for the Hanna salinity checker and judge for yourself whether you wanna trust that. It’s not super reliable.

The cheapest precise easiest to use tools to check salinity are the Tropic Marin precision hydrometer or the Dupla Hydrometer.
They are very fragile, but they are good to check if the calibration of your Milwaukee MA887 digital refractometer or your VeeGee STX3 refractometer is still on point.

 

[LxHowler]

I’ve recently had a post along similar lines to this. I ended up purchasing the tropic Marin hydrometer and found that the Hanna checker was .001 out (reading too low). I know use the hanna checker and keep that in mind.
It’s always best to have multiple methods to test, it shows if one is wildly out.
On another note I have had issues with the brightwell calibration fluid in the past. I made a batch of the diy salinity test fluid, you can find it on here somewhere, and when comparing the brighwell ended up reading 1.033. Since then I’ve never trusted the stuff and only use the diy calibration fluid.

 

[doubleshot00]

I wouldn’t trust either. I would have not bought either and got a Milwaukee or a floating hydrometer.

 

[homer1475]

I wouldn’t trust either. I would have not bought either and got a Milwaukee or a floating hydrometer.

Many, many posts about the milwaukee being off by .003 ppt on every model.

I would not trust the calibration fluid, and DIY my own, then check salinity with the 2.

I have 2 hanna's and using Randy's DIY calibration fluid on it, and my refractometer, they match each other.

Salinity really isn't that critical to be honest. As long as it's somewhere between 1.024, and 1.028 your typically fine.

 

[homer1475]

http://reefkeeping.com/issues/2004-06/rhf/index.htm

 

[daniel_mourra]

Take a look inside your refractometer, where you take the reading, and see whether the temperature compensation is for 20C or 25C.
If doesn’t say that, take a look at the manual.

If you can’t find any information about temperature compensation, I probably wouldn’t keep using that refractometer.
Some of the cheaper refractometers sold for aquarium keeping compensate for the wrong temperature.

Take a look at the reviews for the Hanna salinity checker and judge for yourself whether you wanna trust that. It’s not super reliable.

The cheapest precise easiest to use tools to check salinity are the Tropic Marin precision hydrometer or the Dupla Hydrometer.
They are very fragile, but they are good to check if the calibration of your Milwaukee MA887 digital refractometer or your VeeGee STX3 refractometer is still on point.

Thank you! My refractometer says 20C inside.. would this be correct?

 

[archercorals]

If you have a friend that has a nice reef and you can ask them to test your salinity for you. But floating hydrometer is the most accurate. Tropica marine makes one, but its a little of a pain to use.

 

[vtecintegra]

Don't trust a refractometer or calibration fluid. Get the TM hydrometer. I thought my salinity was good until I did an ICP. It was running low even though my refractometer+fluid said 1.026. I got the hydrometer and it matched the ICP.

 

[TheBear78]

Hydrometer is most reliable.
There are several threads about the Hanna under reading by 0.002 or so. This is my experience too.

 

[Muffin87]

Thank you! My refractometer says 20C inside.. would this be correct?

No. Chuck it away! It needs to correct for 25C

 

[alain Bouchard]

I think you shouldnt care too much, as long as salinity is stable. difference between 1.025 and 1.026 wont change anything for any of your inhabitant.

 

[Floyd-]

I got into this same debate with my swing arm hydrometer, refractometer and Hanna checker. They were close but not the same. Me personally I just use the Hanna and calibrate it with Randy's info for calibration solution.

 

[nothing_fancy]

Its good to have a floating hydrometer like the one made by Tropic Marin. You can use that to judge whatever your using for a quicker salinity checks. My hanna checker reads a bit high even when calibrated compared to the old school hydrometer so I just take that into consideration when I use the hanna checker.

 

[Muffin87]

I think you shouldnt care too much, as long as salinity is stable. difference between 1.025 and 1.026 wont change anything for any of your inhabitant.

He’s complaining that he can’t get a consistent measurement across devices. The only way to get a consistent measurement in having all devices calibrated and compensating for temperature correctly.

 

[alain Bouchard]

He’s complaining that he can’t get a consistent measurement across devices. The only way to get a consistent measurement in having all devices calibrated and compensating for temperature correctly.

and what I mean is to use the same device and stick with it, and even if it shows 1.029 and in reality it is 1.025, it wont make a difference to the inhabitant; a swing in salinity would make a difference, and any one of its devices should be able to detect it. Never forget that, even if you feel like a professional scientist in your fish room with your devices; they are only hobby grade, not lab grade.

 

[vetteguy53081]

Hello

I just calibrated my refractometer with brightwell refractometer calibration standard as per the instructions to 1.026 SG (35%) and my Hanna Salinity chequer using the Hanna Salinity Calibration satchet g1.026 (35%)..

When i test my aquarium water…. my refractometer displays 1.028…. Hanna says 1.025
Which do i believe??? Both are calibrated 4 minutes ago….

I have both and just calibrated my Hanna which was - WAS . . my trusted checker but I am suspecting it is off

 

[Muffin87]

and what I mean is to use the same device and stick with it, and even if it shows 1.029 and in reality it is 1.025, it wont make a difference to the inhabitant; a swing in salinity would make a difference, and any one of its devices should be able to detect it. Never forget that, even if you feel like a professional scientist in your fish room with your devices; they are only hobby grade, not lab grade.

I don’t think it’s about feeling like a scientist, besides hobby grade doesn’t mean inherently inaccurate or imprecise.
The tropic marine hydrometer is very accurate, and it’s “hobby grade”.
at least one public aquarium is run using salifert test kits; given the investment, they’d get better test kits for on the spot measurements, if money could buy them.

If you never double check your results with a different method, you will never know if your device is actually calibrated or is even broken altogether.
refractive index is very dependent on temperature, I don’t have the data at hand but you may be underestimating how much the wrong temperature compensation can affect the reading.
Personally I’d rather be safe than sorry when investing so much money in livestock.

 

[Nhjmc]

I’m with you on this one. I’ve always trusted the Milwaukee so I think I’m going to stick with that.