Aquarium Salinity Refractometer

This product does exactly what it says easy to adjust to zero and stays consistent 1000 times worth the money!!!

Very impressed with the capability of this instrument for less than $20. When compared to our commercial quality (YSI) equipment, the inexpensive device performs really well. Unfortunately, calibrating with distilled water was not a good 'zero'. Once calibrated against the YSI, the meter then held its own. My suggestion is to calibrate it once, then use it for measuring relative adjustments in salinity. Or, mix your own PPT by salt and water weight (see youtube) then you can get your tank back into its original condition, but you may not know precisely what your salinity PPT is. The meter is quick and easy to use, so maybe measure the pet shop's water then make yours match whatever reading you obtain. :-)

I love this refractometer but I'm going to have to return it. After getting this, I calibrated it against deionized water. After using it on my first mash, I got a reading that was off by about 0.020 (1.050 reading instead of 1.030). Later on, playing around with deionized water, sugar and salt, I discovered that this instrument is very accurate with salinity but not very accurate with dissolved sugars when compared to a hydrometer (LD Carlson 5451). I don't know why or how this could be but it is. Various concentrations of sugar solutions were off on the refractometer compared to the hydrometer, and the greater the concentration the further off the reading. [I did correct the readings for temperature and they were still off.] However, when I tried the same experiment with a salt solution the readings were exactly correlated. Looking back at the product pictures, I see now the scale reads "salinity" with no reference to "wort". I cannot figure out how there would be a difference between specific gravity of salt vs. sugar solutions, but based on my home-experiments with this refractometer, there are. I suspect this would be very good for aquariums. For now, I am going to replace this product for when that is specifically advertised for homebrewing.

Bought this one and a digital one at the same time. Digital stopped giving accurate measurements after the third use and this one will likely continue to measure accurately forever. The plastic flap/cover that goes over the lens has a pin in it to secure it and the pin is slowly working its way out so I need to continually push it back in but for the price this is an excellent unit and accurate.

I can’t believe I didn’t invest in one of these earlier. Calibration was easy with a slight turn of the included screw driver, I was all set. The screw driver doubled as a tool to clear my air intake tube on my Protein Skimmer. No guessing with my old hydrometer and the surface tension/meniscus inability to get an exact reading. Focusing was typical and simple to do. A must have for a saltwater aquarium.

I'm using to add a little salt to my aquarium when my Betta is sick. The scale is too wide for this small amount of salt, but better than a guess. I use a flashlight to light the scale.

I CAN'T EVEN EXPRESS HOW WONDERFUL THIS PRODUCT IS. I WAS SCARED OF IT AT FIRST, THINKING IT WOULD BE CUMBERSOME AND DIFFICULT TO USE, BUT IT IS ABSOLUTELY EASY! YOU JUST PUT A DROP OF WATER ON THE GLASS, DROP THE PLATE OVER IT, AND HOLD LOOK THRU IT WHILE POINTING IT TOWARD A LIGHT SOURCE. THE GAUGE IS SUPER EASY TO SEE / READ. SO MUCH MORE ACCURATE THAN OTHER DEVICES I HAVE HAD, AND I CAN TELL THIS ONE WILL LAST FOREVER.

Works great, good deal, and came fast.