Hydrometer

[Ubergroover]

So I have this coralife hydrometer. Its seems to be all over the place. What is the best way to know what your specific gravity is? What do most people use?

 

[cwalton00]

Refractometer I think BRS has them on sale right now.

 

[leptang]

This might help
https://www.algone.com/salinity-and-specific-gravity-guidelines-for-the-saltwater-and-reef-keeper

 

[Jisko]

I've used this one for about 6 months now and it's been perfect. I normally check my water with both a hydrometer and a refractometer

https://www.amazon.com/gp/product/B005ES6MOQ/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A2W6FPR1E93UUZ

a refractometer is a lot better then a hydrometer because the hydrometer can build up salt and not be as accurate

 

[cloak]

I've been using a $7.99 floating glass hydrometer for about 18 years now without any problems. The only downside IME is that they can break if your not careful, but other than that they're pretty easy to use.
FWIW my parents used to use the same thing back in the late 70's early 80's for their tank. Here it is 2017 and the design is exactly the same. This just goes to show that these things do in fact work, quite well actually.

 

[Koa]

Get a refractometer much more actuate

 

[SethOF]

Get a refractometer much more actuate

Actually not true. They measure different things, one light transmission, the other relative weights. There is correlation between the 2 of course. You can no measure specific gravity which has no units with a refractometer which has results reported as

Specific gravity as measure by a hydrometer is as accurate as you can get. The issue has to do with the both the ability of the person measuring (Note that in chemistry class, using the same materials and instruments students come up with different answers) as well as the quality of the instrument.