Refractometer for Reading Salinity with Calibration Fluid

Refractometer for Reading Salinity with Calibration Fluid
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Refractometer for Reading Salinity with Calibration Fluid

98% Recommend this to a friend (444 of 455)

SKU: 205171

reg. $39.99

Special Price: $27.99

In Stock: 583
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Quick Overview

Why does BRS recommend this?

If you have been using a hydrometer and have never tried a refractometer then you should really invest in one.  They use much less water, and can easily be calibrated for accurate repeatable readings.  For the most accurate readings  you will want to calibrate the refractometer to the solution you will be reading, and that is why we always include a bottle of Aqua Craft Calibration Solution at 35ppt (1.026sg) to keep your reef tanks salinity spot on.

Must have equipment for aquarists! Easily and accurately measure the salinity of your tank. Simple to use and read. This unit automatically compensates for temperature. FREE Salinity Calibration Fluid included. Calibrating your unit ensures correct salinity readings.


Full Details

Refractometers are one of the best pieces of equipment an aquarist can purchase. It not only ensures accurate measurements of salinity but it is also infinitely easier to use and read.


Range: 1.000 - 1.070 SG


Comes with the following:

  • Dropper
  • Carrying Case
  • Screw Driver for calibrating
  • Adjustable eyepiece
  • Salinity Calibration Fluid. Calibrates to sg 1.026 (35ppt)


Steps to calibrate your unit:

1) Using the dropper place a few drops of the solution on the glass and close the lid.

2) Looking through the unit and turn the screw until the unit reads sg 1.026 (35ppt)

3) Screw the cap back on your calibration solution for storage. It is important that the cap is on tight or water will evaporate and ruin the solution.


*** Do not calibrate using RO/DI water as this will not give accurate readings for saltwater aquariums***


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  • Works great but hard to read with glasses. By Brian on 9/20/2017

    This is great but I wish the eyepiece was larger or somehow better suited to reading with glasses.
  • Works well By Nick on 9/18/2017

    Very easy to use
  • I like that you can calibrate it! By sh4rkbyt3 on 9/14/2017

    Wanted to check the accuracy of my Instant Ocean Hydrometer after reading a few less than good reviews and some complaints on a few forums. Well having to be honest, the hydrometer was spot on in it's accuracy.
    One thing I've dealt with through the years is the "know it all's" who seem to think what they use or how they do it is the best. Sometimes that's true but a lot less than you'd think.
    This was one of those points I proved to myself. The hydrometer is just as accurate as the refractometer! It's good to be able to check for accuracy though and have a reference point.
  • Very good product By Troy on 9/5/2017

    Extremely accurate and well built.
  • Great Buy ! ! By Fudsey on 6/25/2017

    This is my 1st Refractometer and I love it. It works great and although it may seem hard to see in some light, just reorient yourself to the light and it becomes clear. Just be on the safe side, I calibrate it every time and usually it is spot on. Only had to adjust it a few times.
  • Good By Nick on 5/11/2017

    Does what it's suppose to.
  • Love it By DW on 4/21/2017

    Went from 2 instant ocean hydroneters tbat read different numbers consistently. Not just different from each other, but even after tapping bubbles out I'd never get the same two readings...

    Yea, I'm good..
    Got this guy and love it. Only complaint is I should have purchased it sooner
  • Fantastic product By Lerch on 4/2/2017

    This is my first time using a refractometer and I love this product. Very accurate and easy to use. I no longer worry where my salinity value is at.
  • A Necessity By Michael on 3/31/2017

    Been out of reef keeping for over 10 years. Starting back up and bought the usual floating dial salinity monitor as I was use to. Saw the great price and had to quickly upgrade. So glad I did salinity levels were not even close floating needle when filling tank said 1.025 checked it with this after quick calibration check and found I was only at 1.021. Glad I was only starting the tank and not relying on the cheap gauge when I begin to add aquatic life to the tank.
  • Much better than Red Sea By Michael on 3/25/2017

    I had the Red Sea refractometer and was concerned that it could lose calibration in minutes. This unit is much easier to read, feels better built, better price, and seems to hold calibration better. Highly recommended.
  • A must have By Chad on 3/25/2017

    I use this constantly. Whether making fresh salt water or acclimating fish or corals it is always being used.
  • Great item! By Mamatoby on 3/18/2017

    We've needed a refractometer for some time. After searching and searching, I decided to come to brs. I just couldn't trust other sellers. Once received, my husband fell in love with it! It's simple to use. For those that complain about the lines being too close, you either probably want to get your eyes checked or focus it until you can read it. I wear glasses and it was super blurry when we got it. Did some fine tuning and it's perfect now. We love it. We recommend it! Thanks brs!


Ask a question

Product Questions

*** Do not calibrate using RO/DI water as this will not give accurate readings***
All my water is from RO/DI water, how do you calibrate this?
Question by: Larry on Dec 23, 2013 11:14:00 AM
Hey Larry,
You calibrate it using the included 35ppt/1.026 calibration solution. The solution is a known standard, so you put that on the slide and then adjust the refractometer to 35ppt/1.026.
Answer by: Bulk Reef Supply on Dec 23, 2013 11:14:00 AM
Where can I get the calibration solution?
Question by: Ken on Oct 9, 2017 2:47:00 AM
Hey there,
Thanks for getting in touch with us in regards to calibration solution for this refractometer. You can purchase more of this on the page that I have linked below. I can say that the included bottle of solution will last quite a while. Please let me know if there is anything else that we can assist with. Thanks!
Answer by: Tyler Schafer (Admin) on Oct 14, 2017 3:39:00 PM
Whats different between the less expensive ones and this? Looks the same and is calibrated for seawater.
Question by: Mike J on Jan 15, 2017 4:43:00 PM
Great question! We carefully select our products here at BRS and we have tested many of these refractometers. We recommend this over the others we have tested, due to its build quality, accuracy, and life of calibration. :-)
Answer by: Randy (Admin) on Jan 16, 2017 12:58:00 PM
Is this unit calibrated specifically for seawater? Or seawater and brine. I was looking at red seas refractometer and theirs is calibrated for seawater only. I know that brine differs from seawater.
Question by: jeremy on Jan 17, 2016 7:09:00 PM
Great question!
The refractometer is set up for levels around 1.026 SG or 35 PPT. Unfortunately these are not designed for brine water levels. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Jan 26, 2016 6:39:00 PM
So the number I read is the one right below the blue right? Sorry I'm new to this. Thanks.
Question by: Anthony Almirall on Dec 29, 2016 10:03:00 PM
Great question! You are correct! Your reading will be the line that is closest to that blue/white division line. :-)
Answer by: Randy (Admin) on Jan 9, 2017 8:30:00 PM
Does this have an adjustable eyepiece? These old eyes require it to focus right.
Question by: Tom Coon on Mar 24, 2016 5:08:00 PM
Great question!
This will have an adjustable eye piece for focus. Feel free to let us know if you have any further questions!
Answer by: Connor (Admin) on Mar 24, 2016 5:20:00 PM
So I received my Refractometer today and the calibration fluid says 35 ppt @77 deg when calibrating should the solution be @77 degs. The Refractometer says calibrate it at 68 degs. Or does this matter
Question by: Jeff on May 3, 2017 2:02:00 AM
Hey there,
These recommendations from the manufacturer are due to the temperature at which the refractometer was calibrated, and in the case of the fluid, the normal aquarium salinity at the typical aquarium temperature. In the case of our use, the temp of the fluid sample will rapidly match the temp of the refractometer, and as these are ATC units, they will adjust for minor temperature differences. What we recommend is that you keep and calibrate your unit at the temp (most likely room temp) at which you will normally take your readings, and try to use a consistent light source as well.

Happy reefing!
Answer by: Zack (Admin) on May 8, 2017 12:04:00 PM
In your answer about accuracy, you state that it is +/- 0.01 SG. That would mean, if I get a reading of 1.026, the true value could be anywhere from 1.016 to 1.036. That would be very unreliable. Did you mean to write +/- 0.001? That would make this refractometer twice as accurate as the Milwaukee electronic refractometer, which would be great. Which is it?
Question by: Ed Courtney on Jun 5, 2017 11:51:00 AM
Hi Ed,

Sorry about the typo there, and thanks for bringing that to our attention! That should actually read accuracy +/- .001 SG!

Happy Reefing!
Answer by: Zack (Admin) on Jun 13, 2017 2:11:00 PM