Aquarium Salinity Refractometer with ATC Function,Saltwater Test Kit for Seawater, Pool, Aquarium, Fish Tank...Dual Scale: Specific Gravity & Salt Percent

The price is just unbeatable for the quality your getting.Don't even think about it just buy it.

Ordered a 1.026 salinity calibration solution to standardize. Problem is something must shift internally between use. I have to calibrate every use as meter will shift as much as +/- 0.004. Doesn’t seem like a huge number but when trying for stability in reef aquariums it’s a big deal.Edit: After about a month of use the refractometer became stable and did not require continuous adjustments. Moved rating to four stars.

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. :-)

Just got my tank set up a few weeks ago and the guy setting up my tank told me to get this. It is very easy to use. You just put a drop of water on the end then look through the hole on the end

It's easy to use, exactly what I needed to measure the salinity of the ocean water for my hermit crabs. It should mention you need distilled water and a very small screwdriver to calibrate it, but it was almost perfectly calibrated.

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.

Easy to use. Serves its purpose

Whenever I bring things home from the pet store the salinity always read 1.030 and I was thinking wow they're salinity is high there. Then I took the refractometer over a friend's house which he knows his spot on 1.025 but again this refractometer tested at 1.030. I calibrated it with RODI water and it was not accurate. It's consistent You just have to make sure you dial it in and check it against other tanks.