Fluval Sea Hydrometer provides an accurate and convenient method of measuring specific gravity and salt level in marine aquariums. Compact and easy to use, the hydrometer can be permanently installed inside the tank for continuous readings.
Its slim, low-profile design camouflages well inside the tank and will not diminish the aesthetics of the aquarium. It can also be used as a portable device, allowing you to take samples simply by submerging it in the water. It features large, easy-to-read markings with ideal salinity range clearly marked in green for clarity.
Fluval Sea Hydrometer, 21st Mar 2016
Reviewer: Stephen Harris
Not on par with any refractometer of course, but i find the fact this hydrometer can be stuck on the tank, or used by filling with some aquarium water very handy, and for 10 euro, who could complain.
The scale is extremely easy to read,and the big arm makes it easier. Once its washed out with freshwater after every use to stop and build up of salt, i can't see why the beginner would not invest in one of these like I just did.