Best Way To Measure Salinity? Hanna Marine Salinity Tester or Refractometer?

[EricR]

Does it matter if it’s iodized table salt or sea salt ?

It is interesting that Randy specifically mentions "Morton's Iodized Salt" but my unsubstantiated guess is that he's comfortable enough with that and didn't want to worry about people trying OTHER common salts on the market that could potentially have other ingredients/impurities/etc... but I don't know anything for sure.

One puzzling thing to me is that, for EC (conductivity) standard, he notes 3.29% but that's salt to total (salt + water) so:
salt = 0.0329(salt + freshwater)

Seems easier to simplify and deal with:
salt = 0.034 x freshwater

*unless I totally just misinterpreted everything and it happened to work out for me anyway

 

[gbroadbridge]

Does it matter if it’s iodized table salt or sea salt ?

Yes, I'm pretty certain that the reason Kosher salt is chosen is that it is reasonably pure Sodium Chloride without additives.

Sea Salt contains many other salts so is too uncertain.

 

[KStatefan]

Does it matter if it’s iodized table salt or sea salt ?

Randy has "Morton Iodized Salt" in his article I am guessing that he used that as it was available most places and is consistent. He also gives measurements in volumes so the particle size would be important in those recipes.

 

[Tamberav]

Not all refractometers are equal.

Veegee refractometer. It doesn’t drift often like the cheap ones and it’s quick and easy to use and not a fragile piece of glass

 

[GarrettT]

Not all refractometers are equal.

Veegee refractometer. It doesn’t drift often like the cheap ones and it’s quick and easy to use and not a fragile piece of glass

But how do you effectively calibrate it and check for accuracy? Rodi water?

 

[Reefer Matt]

So I'm just setting up a first Saltwater Aquarium and wondering the best way to test salinity? I have one of those plastic hydrometers but heard they aren't so accurate or reliable?

From what I can gather both those electric/digital testers (conducting testers?) and refractometers need monthly or so calibration (using a 35 ppt solution)?

So in that case, would something like the Hanna Marine Salinity Tester be the best option for the price (was hoping to get a reliable, accurate tester for no more than $100 CAD if possible, I know there's a lot of expensive refractometers some people like).

Thanks in advance for any help!

I have been using a $20 refractometer for the past 5 years with zero problems. Salinity can be kept in a range of 1.024-1.026 sg in a reef aquarium. Some people keep it outside that range too. Lab grade equipment is not required.

 

[Rmckoy]

Randy has "Morton Iodized Salt" in his article I am guessing that he used that as it was available most places and is consistent. He also gives measurements in volumes so the particle size would be important in those recipes.

For example .

 

[KStatefan]

For example .

when a pound container of Morton’s is $1.25 and will make 5+ gallons of solution I would not use anything else

 

[Tamberav]

But how do you effectively calibrate it and check for accuracy? Rodi water?

Some use distilled and some use solutions. Can buy one or make your own.

Handheld Salinity Refractometer

The STX-3 Handheld Salinity Refractometer features the largest, easiest-to-read scale available with clear, sharp figures, screen shading and incredible contrast. This significantly enhances overall precision, even when several different people use the refractometer. The STX-3 also comes with a...

www.veegee.com

Technically…
All that matters is stability so even if it was 1.027 instead of 1.026. It’s not going to negatively impact the tank. I would calibrate it the same way every time.

What would be a problem if it was really 1.027 one time and 1.024 the next instead of say 1.026.

15 years and it’s never swung around or caused problems.

It’s just less annoying to pay for a quality one then to adjust the screw all the time.

 

[Randy Holmes-Farley]

Randy has "Morton Iodized Salt" in his article I am guessing that he used that as it was available most places and is consistent. He also gives measurements in volumes so the particle size would be important in those recipes.

Yes, and it's what I had.

If you go by salt mass, it wont matter much which brand as long as it is dry (you can always bake it if you want).

If you go by salt volume, that could be a lot more variable.

 

[Randy Holmes-Farley]

For example .

While sea salts are mostly a marketing thing (they do not look like seawater, and you wouldn't want them too unless you want diarrhea from magnesium and sulfate), there's no desire to have anything except sodium chloride in the reference.

 

[Randy Holmes-Farley]

Wow that's crazy, BUT if it's that accurate and consistent, why use anything else alongside it?

Because there are situations where it is terribly inconvenient (drip acclimating fish, for example), and it is always less convenient than a good conductivity probe (IME).

I had a TM hydrometer, and a good conductivity meter (Orion model 128) and a cheaper meter (Pinpoint).

I mostly used the Orion, occasionally the Pinpoint, and almost never the TM.

 

[Randy Holmes-Farley]

From what I can gather both those electric/digital testers (conducting testers?) and refractometers need monthly or so calibration (using a 35 ppt solution)?

Just an FYI, not all conductivity meters need frequent recalibration. My preferred model (Orion 128) couldn't be calibrated (only checked for accuracy), and never varied over years.

Nevertheless, it is smart to calibrate or check them frequently.

 

[Rmckoy]

While sea salts are mostly a marketing thing (they do not look like seawater, and you wouldn't want them too unless you want diarrhea from magnesium and sulfate), there's no desire to have anything except sodium chloride in the reference.

This one is apparently salt …
Not epsom ( magnesium sulfate ) at least that’s what I thought …
I might have to double check . I’ve been cooking with it for years … and no scoots

 

[Randy Holmes-Farley]

Wow that's crazy, BUT if it's that accurate and consistent, why use anything else alongside it?

It also requires manual temperature correction. The result from unheated new saltt water will be way off.

 

[Randy Holmes-Farley]

This one is apparently salt …
Not epsom ( magnesium sulfate ) at least that’s what I thought …
I might have to double check . I’ve been cooking with it for years … and no scoots

Correct, that's my point. Sea Salt is mostly a marketing thing as it is mostly sodium chloride and most salt ultimately came from dried ocean water anyway (even if it is mined now).

But for this purpose, we do not want it deviating from sodium chloride, so we should not be looking for anything special beyond table salt.

 

[Randy Holmes-Farley]

Does it matter if it’s iodized table salt or sea salt ?

By mass, no.

By volume, I expect not, unless it very slightly alters the dry bulk density through different processing.

 

[Rmckoy]

Correct, that's my point. Sea Salt is mostly a marketing thing as it is mostly sodium chloride and most salt ultimately came from dried ocean water anyway (even if it is mined now).

But for this purpose, we do not want it deviating from sodium chloride, so we should not be looking for anything special beyond table salt.

Makes sense …
understanding most salt either is mined or collected from dried oceans . I assumed us was sodium chloride ( salt ) and was thinking what’s the difference ?
Why would it have to be specifically “Morton’s” table
Salt

 

[EricR]

Randy, if you see this, tell me if I misinterpreted something.
***for making conductivity standard using a scale

Here's an excerpt from a previous post:

One puzzling thing to me is that, for EC (conductivity) standard, he notes 3.29% but that's salt to total (salt + water) so:
salt = 0.0329(salt + freshwater)

Seems easier to simplify and deal with:
salt = 0.034 x freshwater

...I meant all that from a practical stand-point (meaning as we're weighing out salt vs water to make a standard for EC)

 

[Bfragale]

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