Refractometer

[BeachBumTX]

Hello,

My LFS has a refractometer for $70. I see on Amazon that there are some for $20. Should I be leery about the cheaper price tag? Could they be junky? Thoughts?

FISH ON!!,

BUM

 

[LiveWire]

Now that I use a Hanna Hi98319 I will never use anything else. And they are super easy toi use and very affordable.

HI98319 Marine Salinity Tester

Designed for Simple Aquarium Salinity Testing Hanna Instruments HI98319 Marine Salinity Tester measures electrical conductivity (EC) to determine the salinity of natural and artificial seawater. Within seconds, the salinity and temperature are measured, and then using the temperature reading...

www.bulkreefsupply.com

 

[Specific Ocean]

Now that I use a Hanna Hi98319 I will never use anything else. And they are super easy toi use and very affordable.

HI98319 Marine Salinity Tester

Designed for Simple Aquarium Salinity Testing Hanna Instruments HI98319 Marine Salinity Tester measures electrical conductivity (EC) to determine the salinity of natural and artificial seawater. Within seconds, the salinity and temperature are measured, and then using the temperature reading...

www.bulkreefsupply.com

+1

ease of use, no guess work, doesn’t need to be recalibrated often

 

[ReefersReef92]

I have the amazon refractometer and I find it very accurate. be sure to buy some calibration fluid as well as they aren't always calibrated correctly

 

[DinoMagnet]

+1 on the Hanna. Not to mention temp is also measured

 

[ItalCanadaReefer]

Hello,

My LFS has a refractometer for $70. I see on Amazon that there are some for $20. Should I be leery about the cheaper price tag? Could they be junky? Thoughts?

FISH ON!!,

BUM

I’m also a newer reefer but I personally did not cheap out on this. Salinity is arguably your most important parameter (we are keeping saltwater specimens here), and the cheaper products have had many stories of not calibrating properly and giving inaccurate readings. I personally bought the Poseidon salinity pen. It is quite new so I am not specifically recommending this exact product but something around $100 range is what I’d definitely look for.

 

[Randy Holmes-Farley Verified Community Expert]

Now that I use a Hanna Hi98319 I will never use anything else. And they are super easy toi use and very affordable.

HI98319 Marine Salinity Tester

Designed for Simple Aquarium Salinity Testing Hanna Instruments HI98319 Marine Salinity Tester measures electrical conductivity (EC) to determine the salinity of natural and artificial seawater. Within seconds, the salinity and temperature are measured, and then using the temperature reading...

www.bulkreefsupply.com

While I am a big fan of conductivity, I'm not sure why folks are so focused on the Hanna conductivity meter. There are many brands that have a much longer track record and are much more sophisticated devices.

 

[Woodneers]

While I am a big fan of conductivity, I'm not sure why folks are so focused on the Hanna conductivity meter. There are many brands that have a much longer track record and are much more sophisticated devices.

Do you ahve an example Randy! im in the market for a new toy!

 

[Gtinnel]

I use a cheap $20 refractometer that I bought about 20 years ago and I also use a Milwaukee digital refractometer. I just got the digital one but so far I'm happy with it. IMO getting multiple testing devices and testing solutions (or even better and cheaper make your own testing solution) is more important than the price of one single tester. I'd rather have 2 cheap refractometers than one expensive one.

 

[Randy Holmes-Farley Verified Community Expert]

Do you ahve an example Randy! im in the market for a new toy!

I and a number of others have had great success with used Orion meters that have 4 electrode probes. I used a Model 128, but others have used different models.

Here's a typical meter, but it needs a probe too:

thermo orion a115 conductivity meter | eBay

Works fine, no probe included.

www.ebay.com

 

[Quokka]

Now that I use a Hanna Hi98319 I will never use anything else. And they are super easy toi use and very affordable.

HI98319 Marine Salinity Tester

Designed for Simple Aquarium Salinity Testing Hanna Instruments HI98319 Marine Salinity Tester measures electrical conductivity (EC) to determine the salinity of natural and artificial seawater. Within seconds, the salinity and temperature are measured, and then using the temperature reading...

www.bulkreefsupply.com

+1 to this, so convenient to just dip the probe in my tank/bucket and have some accuracy up to the tenth of a PPT (and seeing the temp).

 

[davidcalgary29]

Amazon refractometers are fine, as long as you don't mistakenly buy one that's calibrated for beer, thus misleading you to raise the SG of your tanks to 1.035. Which happened to someone I know. Okay, I did it! And I screwed up all my builds! All were cycling and had no fish, but still.

I'm now on the Hanna salinity meter train, but use my beerfractometer (now calibrated properly for marine tanks) as an emergency (if forever suspect) backup.

 

[Reefinmike]

The tropic marin precision glass hydrometer is $31 and blows everything else away. Far more accurate and precise. Don’t scoff at the idea of using a hydrometer... this one is very different than the old plastic swing arm pieces of junk.

 

[davidcalgary29]

The tropic marin precision glass hydrometer is $31 and blows everything else away. Far more accurate and precise. Don’t scoff at the idea of using a hydrometer... this one is very different than the old plastic swing arm pieces of junk.

It's out of stock at every place I've checked in Canada, though, and shipping from the EU is 60 bucks...

 

[threebuoys]

I bought a refractometer on Amazon about 7 months ago. After mixing several cups more salt than the instant ocean reef instructions for my new 125 gallon aquarium, I became suspicious and bought a swinging arm hydrometer. The refractometer read 1.020, the hydrometer read 1.029. I had to remove 30 gallons of water to lower to 1.025 I returned the refractometer, reviewed others on Amazon and they all appeared to be made by the same mfg. , so no repeat purchase. Fast forward 6 months, I bought a Ciztada electronic TDS probe for $40 on Amazon. It told me my salinity was 28 ppt. I was expecting 34/35. Just to be sure, I walked over to the Atlantic ocean (I live on the Outer Banks, NC) and took a sample. The Ciztada also read NSWt at 28 ppt. So I got a refund for that device. I've now ordered the recalibration fluid for the Ciztada (which I still have) for another $40. I'll get it next week and try to see if that solves the problem. So far, the only accurate reading I've been able to get is from the floating arm Instant Ocean Hydrometer.

 

[Reefinmike]

It's out of stock at every place I've checked in Canada, though, and shipping from the EU is 60 bucks...

Check your messages, I could help you out

 

[shwareefer]

All refractometers are affected by temperature bigtime ( never understood making them out of aluminum - the most temperature deforming metal). I therefore recalibrate EVERY time I use it. It take 2 seconds with DI water to set a zero value and then do your test. Frankly you could zero with tap water (you'd need rediculous TDS to cause significant error) then do your test and still have higher accuracy than most other methods. The DI and tank water should be the same temperature for highest accuracy.

As for the OP's question about amazon cheapies, they most likely are fine but considering you will buy 1 refractometer in your entire reefing career, just buy the Sybon and be done with it.

I do like the idea of the tropic marin precision glass hydrometer but that thing is huge and you will need a very tall flask to test outside your tank to get an accurate value. Too cumbersome for many.

 

[Randy Holmes-Farley Verified Community Expert]

All refractometers are affected by temperature bigtime ( never understood making them out of aluminum - the most temperature deforming metal).

Not sure what you mean by that.

Most sold to hobbyists are designed to automatically compensate for temperature changes (a feature called ATC). They use a metal pieve taht expands and cotnracts by the exact (or close to exact) that the water is changing refractive index with temperature.

I describe exactly how the ATC feature works here:

Refractometers And Salinity Measurement
http://www.reefedition.com/refractometers-salinity-measurement/

from it:

Temperature and Refractive Index: ATC

It turns out that refractive index is highly dependent on temperature. When using a refractometer that does not account for this effect, temperature changes can be a large source of errors. Most liquid materials expand slightly when heated and shrink when cooled. For a given material, light can pass through it more easily when it is expanded, so the index of refraction falls when materials are warmed. However, the magnitude of this effect is different for every material, and refractometers must somehow take this into account.

Handheld refractometers account for temperature by employing a bimetal strip inside them. This bimetal strip expands and contracts as the temperature changes. The bimetal strip is attached to the optics inside the refractometer, moving them slightly as the temperature changes. This movement is designed to exactly cancel temperature’s effects on refractive index, and generally does a very good job IF the refractometer is designed to cancel out the temperature effects of the specific material being analyzed.

Because many refractometers are designed to use aqueous (water) solutions, the bimetal strip can be designed to account for the change in refractive index of aqueous solutions with temperature, although it may not be perfect in some situations because salts and other materials in the water can change temperature’s effects on refractive index by a small extent (or possibly to a large extent for very concentrated solutions, such as 750% sugar in water, but seawater is not in that category). Other details of this compensation may cause it to be imperfect (for example, the bimetallic strip provides a linear correction while the true temperature effect may be nonlinear), but those issues are beyond the scope of this article, and in general automatic temperature compensation (ATC) is a very useful attribute for aquarists using refractometers.

 

[shwareefer]

I only meant that as a metal, aluminum moves alot with temperature. Making the body out of just about any tool steel with a TiN coating would achieve the same corrosion resistance with much less sensitivity to temperature variations.

Since I always check calibration with DI water and since I quite often have to recalibrate zero, my trust in the effectiveness of ATC is not so high.

 

[Randy Holmes-Farley Verified Community Expert]

I only meant that as a metal, aluminum moves alot with temperature. Making the body out of just about any tool steel with a TiN coating would achieve the same corrosion resistance with much less sensitivity to temperature variations.

Since I always check calibration with DI water and since I quite often have to recalibrate zero, my trust in the effectiveness of ATC is not so high.

I do not believe the problem with temp lies in the expansion and contraction of the body of the refractometer, but in the change in the the refractive index of the water with temperature. Regardless, the ATC is presumably designed to account for any effects.

It is easy to confirm (or reject) the effectiveness of the ATC by measuring the salinity of the same water at different temperatures.