Comments: Nice idea but it doesn't work unless you turn all your pumps off, the flow makes the needle jump making it impossible to read. Save your money.

Comments: Mine does keep accurate readings more or less. But it's so difficult to keep level, don't bother. If you depend on this item to keep your tank, you are in trouble. Mostly a waste of time, try red sea

Comments: Instruction sheet says submerge 6in under water and wait 24hrs before first/initial reading to give hydrometer time to break-in. After one week and the needle not providing any reading, I pitched it in the trash where it belongs. Save your money people!

Comments: This would likely be great for permanent placement into a sump for a quick check on the salt levels. It is extremely sensitive to distance from the water level and being level though, and even at its most accurate readings, it is still not that accurate.
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<br />If you dont have a hydrometer, don't make this your first. If you do have one and would like to permanently mount this either in your sump or tank for a quick idea of the salt levels (so that you can pull out your accurate one and verify), this is perfect for you.

Comments: I have been using my refractometer for over two years and it always gave me accurate reading every time. I bought two of these hydrometers three months ago because I thought it would be nice if I could get a quick reading of the salinity level in my tank at anytime I want. Well, they both have been giving accurate readings until now. One of them showed that the salinity was well below the proper level in one of my tanks and the other one showed that the salinity in my other tank was way too high. I didn't trust these readings at all so I used my refractometer and found the salinity in both tanks to be at 1.024 and 1.025. So, both of these things only worked fine for about three months then started giving me false readings! If you want to buy a hydrometer I would strongly suggest that you invest in a hydrometer instead. DON'T WASTE YOU MONEY ON THIS HYDROMETER!

Comments: For 10 bucks, I decided to give it a try. As of now, it has been pretty pointless. I keep it in display of a 12 gallon. The flow is such that it moves the needle as well as the whole unit, thus preventing any semblance of a reading. Kept in an area of little flow, it may work. So far, I have no luck. But leave it to Oceanic. They rush these "good idea" products to the market, without having thought thru the practicality and usability of the product.

Comments: This is the first submersible I have used that actually keeps correct salinity. It reads on back of the package to wait 24 hours before taking first reading, but mine worked immediately giving me an accurate and reliable reading. I placed this device in my refugium and works very well.

Comments: I bought this planning to stick it in my sump. My sump actually doesn't have that bad a microbubble problem compared to others, but very quickly these microbubbles get into the hydrometer and makes the readings inconsistent.