Lubricate Your Refractometer

[redfishbluefish]

Did you know an unlubricated refractometer will produce funny numbers?


Your refractometer has a hinged cover that goes over the angled plate of the refractometer. What happens over time is the hinges stiffen up from salt deposits, causing this cover to not sit all the way down on the angled plate. You can not see this by your own eye, but believe me, it's not fully resting on the angled plate. When this occurs, the numbers you see are no longer true. Actually this typically occurs slowly over time, and you most likely don't even realize it.

That little hinged door needs to easily and readily flop down onto the plate. If it is stiff, and doesn't fall freely, you aren't getting an accurate reading of your salinity. You can potentially offset this error by frequently calibrating your refractometer with 1.026 calibration fluid (not RO/DI water). Note that this calibration solution could also be termed 35ppt or 53 mS/cm.

However, the best thing to do is to keep your refractometer hinges well lubricated.


Now I know some of you are thinking I'm a nut case. Well, I am, but your refractometer still needs lubrication....and I'll prove it, especially if you have a stiff-hinged refractometer. What I want you to do is to measure the salinity of your tank. Now follow my lubrication instructions below and re-measure your tank (before re-calibrating). Do you see a difference? Please post your results here so others can see the truth.

So how do I lubricate my refractometer without getting lube all over the place?

Let's first see if you have stiff hinges. Take your refractometer and open the "door" so that it is sticking straigh up:

The door should readily and easily fall back down into position, and not stay in this stiffened position. If the door just stays there, you have really stiff hinges, resulting in funny salinity numbers.

A second test is to hold your refractometer upside down and move it back and forth. The door should readily and easily swing back and forth at all hinge points, with extreme ease with each back and forth motion you make. Again, if not, you've got stiff hinges.

So let's lube your refractometer!

I use WD40, but I would imagine other lubs would work just at well. Now I don't simply squirt WD40 on my refractometer....that would be a mess, and who knows what this lube would do to accurate readings? What I do is very carefully dab small amounts of WD40 directly on the hinge pins only.

So what I do is to first squirt a small amount of WD40 into a very small glass. My wife was insistent on purchasing Waterford Crystal Aperitif glasses....don't ask the price. I'm coming up on 40 years of marriage and we've never used these glasses. They sit in our china cabinet, never used......until now. Don't know what an Aperitif glass is? It's a disgustingly small glass that holds a thimble's worth of liquid that is used to serve an Aperitif or Cordial.....pinkies out.

So I'm figuring I've got to get some use out of these overpriced, never used, small glasses, so I squirt a small amount of WD40 into one of the glasses. Please don't tell my wife.

Now using a toothpick or finishing nail, I dab a small amount of the WD40 on the hinge points and then move the door back and forth to work the lube in. You'll actually feel the door free up and move easily as you are doing this.

Continue to do all hinge points with this lubrication, moving the door back and forth as you work that lub in.

Now when you attempt to put that door straight up in the air, it should immediately fall down into position.

Now for those of you doing my little test above, re-test you tank water and let me know what number you're getting....before and after lubing. Otherwise, once you've lubricated your hinges, you need to re-calibrate your refractometer. Now you are all set to get accurate numbers from your refractometer.

Finishing up, how frequently do I lubricate? I would guess it's about once a year, whenever I notice the door isn't swinging down very freely. This timing could vary widely dependently on frequency of use. I'm only doing water changes twice a month, so lube as needed to keep you refractometer humming perfectly.

 

[Crabs McJones]

Good article! I checked mine and it still swings freely, but I'll definitely be aware of it in the future
"Now I know some of you are thinking I'm a nut case. Well, I am, but your refractometer still needs lubrication.." Lol! I love that little bit

 

[ca1ore]

A very good observation. I've had to lubricate mine a few times.

 

[Scrubber_steve]

I calibrate mine using NSW when ever i use it.

 

[redfishbluefish]

@Scrubber_steve , you've sparked my curiosity! How do you know the salinity of the NSW? This will vary dependent on location, time of year, incoming or outgoing tide, rain/runoff, etc....you just don't know what you have.

There are other options over purchasing that small bottle of really, just saltwater, for 8 - 10 US dollars.

One thing I've suggested to some is to visit a fellow reefer's house and, when they're not looking, steal a small vial of their tank water. Actually, if you ask nicely, I'm sure they would give it to you. Now you only do this if this friend uses a calibrated refractometer and knows the salinity of their tank. You now have calibration solution and it didn't cost you anything.

The second way is to make your own calibration solution. You end up making so much, for pennies, you can share it with all your reefer friends, resulting in them having a happy face. I won't go into the details, but simply weigh the salt and water, mix, and you're done. All the details are in Dr. Randy Holmes Farley article HERE. Since so many of us now have kitchen scales, I'd recommend the weighing method for making this standard.

 

[dbl]

Good article Paul and something I would have never thought of. Great observation.

 

[KJ]

Great article Paul

 

[redfishbluefish]

Good article Paul and something I would have never thought of. Great observation.

Thanks David. I actually "discovered" this about 4 - 5 years ago, and just this past week, I had to re-lube my refractometer, and figured I'd share this little secret with the community. The way I discovered this was that I measure and count cups of salt to make up new water. For me, 15 cups of IO to 25 gallons of water. Most times it's pretty much spot on, and some times, minor adjustments of a pinch more salt or a shot of water. This one time I measured out the salt and then had to do a major adjustment. I simply figured I counted wrong or missed on filling the measuring cup all the way. The next time I made new water, same thing. But now I re-calibrated and found I had to adjust the refractometer to get it into spec. Closely looking at the refractometer, I found the door was very stiff. So I did my little lube thing and now found the reading was way off of what I had just tested before lubing. Recalibrating the refractometer did the trick and now all is good. Free swinging door and perfectly calibrated refractometer.

 

[redfishbluefish]

Great article Paul

Thanks KJ.


Something else hit me about refractometers that nobody ever tells you.....Whatever light source you use to calibrate your refractometer, use that same light source to do your measurements. That is, if you use natural sunlight to calibrate, use it to do your measurements. If you use a fluorescent bulb in a light fixture, always use that. Similarly, with an LED light bulb. And finally, if you're using an incandescent light bulb, stop now, unscrew that antique, throw it in the trash, and replace it with an energy saving LED. Never calibrate with one type of light source and measure with another light source. Wavelength matters!!!

 

[Crabs McJones]

Thanks KJ.


Something else hit me about refractometers that nobody ever tells you.....Whatever light source you use to calibrate your refractometer, use that same light source to do your measurements. That is, if you use natural sunlight to calibrate, use it to do your measurements. If you use a fluorescent bulb in a light fixture, always use that. Similarly, with an LED light bulb. And finally, if you're using an incandescent light bulb, stop now, unscrew that antique, throw it in the trash, and replace it with an energy saving LED. Never calibrate with one type of light source and measure with another light source. Wavelength matters!!!

Any reason for getting rid of the incandescent? Does it mess with the result? I switched my whole house over to LED about a year ago, but just curious

 

[redfishbluefish]

Any reason for getting rid of the incandescent? Does it mess with the result? I switched my whole house over to LED about a year ago, but just curious

It only messes with your electric bill. Just like any light source, it could be used with your refractometer, but same deal....calibrate with incandescent, measure with incandescent.....and then pay your bill. Back in 94/95, when compact fluorescents came out, if you changed out your house with these bulbs, payback was about one year. LED's push that electrical savings that much further.

 

[DSC reef]

Thanks KJ.


Something else hit me about refractometers that nobody ever tells you.....Whatever light source you use to calibrate your refractometer, use that same light source to do your measurements. That is, if you use natural sunlight to calibrate, use it to do your measurements. If you use a fluorescent bulb in a light fixture, always use that. Similarly, with an LED light bulb. And finally, if you're using an incandescent light bulb, stop now, unscrew that antique, throw it in the trash, and replace it with an energy saving LED. Never calibrate with one type of light source and measure with another light source. Wavelength matters!!!

+1000 to this!

 

[Crabs McJones]

It only messes with your electric bill. Just like any light source, it could be used with your refractometer, but same deal....calibrate with incandescent, measure with incandescent.....and then pay your bill. Back in 94/95, when compact fluorescents came out, if you changed out your house with these bulbs, payback was about one year. LED's push that electrical savings that much further.

Agreed. As stated above, I switched my whole house over to LED, and then for some odd reason I went to metal halide t5s on the tank lol. So i save on my house lighting but the tank lighting probably puts be right back to where I was lol!

 

[NeuroticAquatics]

I’m trying to follow the link to the article and it is taking me to a “New Shrooms” thread.

 

[ScooterV]

I just recently noticed this on mine. I'd have to tap the top to get it to make even a clear reading, accurate or otherwise. I used vegetable oil though and a manual workout and seems to have done the trick, at least for now. Once calibrated it used to remain dead on for a long time, then I found I was having to re-calibrate every time I looked at it. When the line itself was no longer even clear I finally figure it out. At least with the constant calibration it doesn't look like I was ever off by enough to matter, other than irritation

 

[redfishbluefish]

I’m trying to follow the link to the article and it is taking me to a “New Shrooms” thread.

Not sure why that's happening.....Try THIS LINK.

 

[siggy]

Great reminder, a couple of drops could have saved me a lot of headaches.

I asked a similar question a while back only I was asking about the calibration screw. Its totally corroded and I was unable to adjust so I had to purchase another. Ironically I received that same Aqua-Craft solution with my replacement and It reads .38 on my Milwaukee.

That was a crazy period between a new apex probe(un-trustworthy), a rusted refractometer out of cal. and a new one with bad solution So I purchased a Milwaukee and THAT came in defective and required a month to receive my replacement:mad: ....So I definitely see the need to lubricate and maintain your equipment .....

 

[redfishbluefish]

Thanks for the tip about the adjustment screw. Mine has a plastic cap that protects it from saltwater.

However, next lube job I do, I'm going to hit that screw with a couple dabs of WD....can't hurt.

 

[ca1ore]

Whatever light source you use to calibrate your refractometer, use that same light source to do your measurements.

Also true - spectrum does matter. Also, if you do lucubrate the hinge, makes sure none of it gets on the refracting face, that will ******** up the reading also.

 

[siggy]

Thanks for the tip about the adjustment screw. Mine has a plastic cap that protects it from saltwater.

However, next lube job I do, I'm going to hit that screw with a couple dabs of WD....can't hurt.

ya I lost mine and dunking the unit wasn't good either, noob stuf