Lubricate Your Refractometer

[MnFish1]

That doesn't get to the crux of the article though; looking at the same sample shouldn't change (according to the link) but calibrating under one and observing a sample under another would. I just didn't word it properly in the first post.

Well so we’re on the same page. I know what the article says. But for it to be ‘true’ ie significant in real life it would suggest that looking at any sample under different lights would make a difference. Ie let’s say I calibrate my refractometer with an incandescent bulb. And measure my sg at 1.025. I then take the refractometer and look at the sample under daylight and it remains 1.025. I have now just used a different light source than the one I calibrated my refractometer and the results are the same. If I use my led lights on my tank and the result is 1.025 what does that tell you? It tells me that with the different light sources available to at least me, there is no difference. Even though in theory
There could be.

 

[hfx987]

I still haven't got my refractometer yet (still slowly setting up my first reef tank) - but I did enjoy your article.
The glassware choice reminded me of many years ago coming home to my flatmate chopping up a certain herb in my Christofle martini glass.
He saw the look on my face and said "your fault - you taught me 'the best, or nothing'".
I couldn't argue :)

 

[MnFish1]

I still haven't got my refractometer yet (still slowly setting up my first reef tank) - but I did enjoy your article.
The glassware choice reminded me of many years ago coming home to my flatmate chopping up a certain herb in my Christofle martini glass.
He saw the look on my face and said "your fault - you taught me 'the best, or nothing'".
I couldn't argue :)

Then there was the time I put the pieces of the Berlin Wall into the Wine glasses from my wife's grandmother (yes crystal) (yes - a poly-something mold) (yes the top of the glass was smaller than the base). Yes - I was crucified....(figuratively)

 

[DirtMcGurt]

The universe put this this article in my path. I've been struggling with accuracy in salinity the last 3 days and my hinge pin is corroded. Also, I need to by some calibration fluid. I've always used RO water. You got 2 of my birds with this stone! Thanks!

 

[tr3]

Great article! Definitely will be lubing my hinges. The way I have always checked mine (not the best way) is I have my LFS check their water when I buy something, then I check their water to see if we have the same readings? So I guess I should get some calibration fluid. Question about the fluid. Do you have to make sure the calibration fluid is a certain temp before calibrating? Would being to cold or to warm throw off the calibration?

 

[Brew12]

Great article! Definitely will be lubing my hinges. The way I have always checked mine (not the best way) is I have my LFS check their water when I buy something, then I check their water to see if we have the same readings? So I guess I should get some calibration fluid. Question about the fluid. Do you have to make sure the calibration fluid is a certain temp before calibrating? Would being to cold or to warm throw off the calibration?

The amount of fluid used in calibration and testing is very small. It will almost immediately go to the same temperature as the refractometer. Temperature compensation is done for the refractometer, not the water, so no need to get the fluid to any specific temp.

 

[tr3]

The amount of fluid used in calibration and testing is very small. It will almost immediately go to the same temperature as the refractometer. Temperature compensation is done for the refractometer, not the water, so no need to get the fluid to any specific temp.

Ok one more question then.. I keep my house at 70, does that mean I need my meter to be kept in a warmer place? Maybe im just thinking to much into it..

 

[Brew12]

Ok one more question then.. I keep my house at 70, does that mean I need my meter to be kept in a warmer place? Maybe im just thinking to much into it..

As long as your refractometer has ATC it doesn't matter. Otherwise you just need to make sure you calibrate it at the same temperature you use it at.

 

[tr3]

As long as your refractometer has ATC it doesn't matter. Otherwise you just need to make sure you calibrate it at the same temperature you use it at.

I feel dumb.. I have always seen atc on my meter, but never thought about what it meant. You learn something new everyday. Thank you, and again great article!

 

[saltyhog]

Man I can't get the hinge on my old one to loosen up yet. I've been working it and putting more oil on it every time I walk by it but it's not there yet.

 

[Brew12]

So, I did some testing on the color spectrum thing. As with others, I saw no difference in readings. Using a controllable light in a darkened room I calibrated my refractometer using nothing but 430nm blue lights. I then tried to read it using 670nm red lights. No discernible difference. I tried to take pictures, but my phone didn't care for the extreme colors, and there isn't anything worth seeing anyway.

I can't explain the discrepancy yet, but I am digging into it. Maybe @Dana Riddle can join in and set this straight. This is the post in question.
https://www.reef2reef.com/threads/refractometers-and-the-color-of-light-used-important.174558/

 

[mta_morrow]

People don't know what they are? :eek: How do you serve a proper formal dinner without getting the taste buds ready? o_O

Alabama fine china

 

[Dana Riddle]

So, I did some testing on the color spectrum thing. As with others, I saw no difference in readings. Using a controllable light in a darkened room I calibrated my refractometer using nothing but 430nm blue lights. I then tried to read it using 670nm red lights. No discernible difference. I tried to take pictures, but my phone didn't care for the extreme colors, and there isn't anything worth seeing anyway.

I can't explain the discrepancy yet, but I am digging into it. Maybe @Dana Riddle can join in and set this straight. This is the post in question.
https://www.reef2reef.com/threads/refractometers-and-the-color-of-light-used-important.174558/

I had never given this much thought, as I have always used a white light source for my refractometer (necessary for determination of some of the colorimetric tests I run.) I'll take a look at this (probably after I get back from MACNA.)

 

[redfishbluefish]

@Dana Riddle , thanks for the reply. Although the purpose of my article was the importance of lubricating the hinges on your refractometer, many have focused on the comment I've made about the importance of wavelength on refractometer reading. Without question, wavelength has an impact on the index of refraction....it's science (some might argue physics). However, after looking into this, the "crudeness" of our handheld refractometers might not be overly subjected to changes in wavelength.


If you look at bench top refractometers, they produce a monocromatic wavelength at 589 nm (sodium D-line). This produces a crisp "line" with a degree of resolution of 0.00001 units. Scientists can compare numbers from around the world because they are using the same wavelength of light to get a reading.

Handhelds only have a degree of resolution of 0.001 units of resolutions, and on top of that, if you're viewing through a multiwavelength light, the "line" of focus is blurred.....it's not a crisp line because of the multiple wavelengths of light. I believe what folks are seeing using different light sources is this "crudeness" in these handheld refractometers we have. With that said, I'd still suggest using a similar light source in calibrating and reading your refractometer.

 

[Dana Riddle]

@Dana Riddle , thanks for the reply. Although the purpose of my article was the importance of lubricating the hinges on your refractometer, many have focused on the comment I've made about the importance of wavelength on refractometer reading. Without question, wavelength has an impact on the index of refraction....it's science (some might argue physics). However, after looking into this, the "crudeness" of our handheld refractometers might not be overly subjected to changes in wavelength.


If you look at bench top refractometers, they produce a monocromatic wavelength at 598.2 wavelength (sodium D-line). This produces a crisp "line" with a degree of resolution of 0.00001 units. Scientists can compare numbers from around the world because they are using the same wavelength of light to get a reading.

Handhelds only have a degree of resolution of 0.001 units of resolutions, and on top of that, if you're viewing through a multiwavelength light, the "line" of focus is blurred.....it's not a crisp line because of the multiple wavelengths of light. I believe what folks are seeing using different light sources is this "crudeness" in these handheld refractometers we have. With that said, I'd still suggest using a similar light source in calibrating and reading your refractometer.

Good job on your article - I just never thought about lubricating the hinges. Do you think lubrication, if not cleaned off the lenses might alter the refractive index? If so, how would you recommend cleaning them?

 

[redfishbluefish]

Thanks Dana for your kind words. Please check your refractory to see if it has stiff hinges. :cool: . I've also never noted lube on the glass door area. The lube is carefully dabbled directly on the hinge pin area....very small amounts.

Now that said, I actually tested WD40 with the refractometer. With the glass plate having a blob of water, one drop of WD was added. It immediately changed the surface tension of the blob, as water ran off the device....but still enough liquid to have full coverage under the door. Reading before WD, 1.025; reading after, 1.026.

I also put 100% WD40 on the refractory and now only saw tan undifferentiated light with no line to read.

Cleaning was with a glass cleaning product (similar to Windex). I'd imagine IPA (isopropyl alcohol) would work just as well.

 

[Dana Riddle]

Thanks Dana for your kind words. Please check your refractory to see if it has stiff hinges. :cool: . I've also never noted lube on the glass door area. The lube is carefully dabbled directly on the hinge pin area....very small amounts.

Now that said, I actually tested WD40 with the refractometer. With the glass plate having a blob of water, one drop of WD was added. It immediately changed the surface tension of the blob, as water ran off the device....but still enough liquid to have full coverage under the door. Reading before WD, 1.025; reading after, 1.026.

I also put 100% WD40 on the refractory and now only saw tan undifferentiated light with no line to read.

Cleaning was with a glass cleaning product (similar to Windex). I'd imagine IPA (isopropyl alcohol) would work just as well.

Wonderful! Thoughtful comments such as this are a pleasure to read! Thanks!

 

[Tajaba]

I just wanna shout out to the OP of this article. I managed to revive my 6 years old refractrometer with this neat trick yesterday. Now at least it doesn't swing 2ppt depending on how I close the lid lol!

 

[Aquainas]

Great article, certainly one of those "tricks" you never here about! I personally avoid getting the hinges wet, for this reason my almost 10 year old Milwaukee is still going strong. However I myself have made the mistake of using different light sources to calibrate/read so that additional tidbit was priceless!

 

[jzw]

hey folks, please answer this, i've been wondering for months:

why the holy heck are there 2 sets of hinges on refractometers?

it seems 1 hinge would do, and be more consistent. cause unless both sets of hinges are swinging perfectly, every time you wipe it, the angle of the two hinges... changes -- lol. my lower hinge is really sticky, been smashing the lid down pretty hard with my fingers trying to get the dang 2 hinges 'flat.'... uggg. lubing now :p