Red Sea Seawater Refractometer (Reef Spec) High Accuracy
Most refractometers used within the aquarium hobby are not specifically designed for reef aquariums and use an algorithm for the measurement of brine (NaCl - rather than seawater) and at a temperature of 15oC/59 0F rather than 25oC/77 0F. Thus, a measurement deviation of up to 1.5ppt is possible, which can have a significant adverse effect on coral growth and coloration. The PPT scale on Red Sea's Seawater refractometer is calculated using an algorithm for seawater and therefore will give a reading of the Absolute Salinity of seawater. The PPT scale on regular salinity refractometers are calculated using an algorithm for Brine. Using a Brine refractometer for Seawater will give an error of approximately 1.5ppt in the salinity reading.
- Directly reads the absolute salinity of seawater at 25°C/77°F ( No need for seawater or temperature compensation factors)
- Specifically designed for the ionic content of seawater (NSW) for more accurate salinity measurement (industry standard refractometers are calibrated for salt brine ).
- Calibrated for seawater (NSW) at 25oC/77oF, the normal temperature range for reef aquariums (most standard refractometers are calibrated at 15C/59F ).
- Easier to read, higher resolution display, focussed to the relevant range for reef aquariums of up to 40ppt
- Includes Integrated Automatic Temperature Compensation (ATC) for accurate measurement at standard ambient temperature.
Red Sea Seawater Refractometer (Reef Spec) High Accuracy
Most refractometers used within the aquarium hobby are not specifically designed for reef aquariums and use an algorithm for the measurement of brine (NaCl - rather than seawater) and at a temperature of 15oC/59 0F rather than 25oC/77 0F. Thus, a measurement deviation of up to 1.5ppt is possible, which can have a significant adverse effect on coral growth and coloration. The PPT scale on Red Sea's Seawater refractometer is calculated using an algorithm for seawater and therefore will give a reading of the Absolute Salinity of seawater. The PPT scale on regular salinity refractometers are calculated using an algorithm for Brine. Using a Brine refractometer for Seawater will give an error of approximately 1.5ppt in the salinity reading.
- Directly reads the absolute salinity of seawater at 25°C/77°F ( No need for seawater or temperature compensation factors)
- Specifically designed for the ionic content of seawater (NSW) for more accurate salinity measurement (industry standard refractometers are calibrated for salt brine ).
- Calibrated for seawater (NSW) at 25oC/77oF, the normal temperature range for reef aquariums (most standard refractometers are calibrated at 15C/59F ).
- Easier to read, higher resolution display, focussed to the relevant range for reef aquariums of up to 40ppt
- Includes Integrated Automatic Temperature Compensation (ATC) for accurate measurement at standard ambient temperature.
About Salinity
Salinity is a general term describing the concentration of salt in water. However, solutions of different type of salts have different refractive indexes. Brine is a solution of Sodium Chloride (table salt) that contains 2 chemical elements. Seawater contains approximately 70 chemical elements that include Calcium, Magnesium, Potassium etc. in addition to the Sodium Chloride. Seawater and Brine of the same salinity (i.e. the same weight of salt/liter) have different refractive indexes and will give different salinity readings if measured on the same refractometer.
Refraction & refractive index
All transparent materials such as liquids refract (distort) light. All transparent materials refract light differently and have what is called a “refractive index” which means how much a particular material distorts light. Different concentrations of the same liquid have different refractive indexes. The scale of a refractometer is calculated by using a mathematical algorithm that relates the measured refraction to its concentration for a specific liquid.
Refractive index and temperature
The refractive index of liquids change with temperature and therefore has a major effect on measuring salinity with a refractometer. The algorithm for defining the PPT (and S.G.) scale for a refractometer is calculated for a specific temperature. PPT readings from refractometers that are not calibrated for reef aquariums (i.e. 25oC) need to be adjusted according to a conversion table to give the actual PPT at the aquarium temperature. This is often a cause for misinterpretation of refractometer readings. For example, using a seawater refractometer calibrated at 20oC will give a PPT reading that is approximately 1-1.5ppt lower than the absolute salinity of the same water sample at the normal aquarium temperature of 25oC.
Therefore, Red Sea’s Seawater Refractometer calibrated at 25°C/77 0F directly reads the absolute salinity of seawater with no need for temperature compensation factor)
ATC – Automatic temperature compensation
Temperature is probably the biggest cause of wrong readings with a refractometer. Calibration and testing of water samples should be done after the refractometer and water sample have equalized at the correct temperature. Automatic temperature compensation (ATC) compensates for a few degrees of difference between the ambient temperature and the calibrated temperature of the refractometer. Larger temperature variations will give an error of approximately 1.0ppt in the salinity reading. ATC does not adjust the PPT reading of a refractometer to the temperature of the aquarium!
Item No. TE-RS-RF
12 Reviews
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VERY ACCURATE
MY SWING ARM HYDROMETER WAS WAY OFF. I CHECKED MY SALINITY LEVEL WITH MY RED SEA AND THREE OTHER LFS REFRACTOMETERS AND THEY WERE ALL IDENTICAL .
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Great equipment Highly Recomended
I've used others at work. This one is real easy and clear to read. I've read other reviews about it falling out of calibration. It took me about 3 times to get it cal'ed in when I first bought it. It's been dead nuts ever since. Also if you clean your dropper with RO/DI after every use. Make sure you get tank water flushed in and out pretty good before taken your reading. No issues with it. I HIGHLY recommend this refractometer.
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Excellent Product!!
First refactometer used !this is the Cadillac tested against a friend's and red sea was dead on! Friend showed where he would have to calibrate because of various reading red sea refractor was consistent great must have tool for reef keeping.
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Refractometer Review
Awesome refractometer. Very Well Built. Excellent Instructions. Well Worth The Price. THANKS, AQUACAVE !
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Excellent Quality
I am extremely happy with the quality of this refractometer. The quality of the construction is sturdy and built to last. Having been a professional winemaker, I would say this compares well well against winemaking refractometers. The case is sturdy enough to keep it safe yet minimalistic enough to be easy to store out of the way. I would certainly purchase this again if given the opportunity.
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Excellent
Well worth the money. Stright forward and easy to use. Nice protective case keeps refractometer, sample dropper, and adjustment tool in place and accessible. Instructions included take all the guess work out of using it. I would definitely recommend this to a beginner or seasoned reefer.
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Great product, throw that swing arm hydrometer away
Be spot on with your salinity level with this. One word of caution, calibrate it before you use it the first time. I was so excited to test it, I forgot and gave myself quite a scare. Now it is a habit to check the calibration before testing.
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Easy to use and accurate
This refractometer is well worth the money. It is easy to use; just drop some water on the glass, close the lid, and wait a few minutes and that's it. Much better than the swing arm style.
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Excellent
Excellent quality and very accurate. I would recommend this product to everyone!
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Way more accurate than a hydrometer.
Worth the price! This item is so much more accurate than a swing hydrometer. If you want an accurate specific gravity measurement, this is a must!
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Very NIce
Very useful tool, easy to read scale. A+
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great
Great product simple to use and waaaaay more accurate than a hydrometer.
