Selecting an accurate Hydrometer

[vsiege]

There seem to be two popular plastic Hydrometer's out there that most stores carry but I wonder if these are accurate. I know this isn't an expensive item but I would like a suggestion on whether I should pick up the glass-type or plastic-type.

 

[tnwillia]

Here is what you need. Have fun!

Refractometer for reading salinity w/ Free Calibration fluid - English

 

[waterdawg413]

the only accurate hydrometer that i know of is called a refractometer

 

[nanoreefing4fun]

+3 ^

 

[BigAl07]

There is a VERY accurate "Hydrometer" but IMHO not an accurate "Swing Arm" hydrometer.

A "Swing Arm" hydrometer is something you use until your refractometer comes in. It's decent in accuracy for "rough guestimates" so long as it's cleaned and stored correctly.
Swing Arm Hydrometers

Now on to a VERY accurate Hydrometer called "Bulb Hydrometer, Floating Hydrometer or Scientific Hydrometer" This is an extremely accurate unit but requires a very good eye, calm water and isn't really very "Reefer Friendly". I have one and it's COOL to have but just not easy to use and it's very fragile.

Floating/Scientific Hydrometer

If you're going to have a Salt Water tank for more than a month you might as well get a refractometer and stop wasting your time and money on "toys". Tom linked to one that's a great deal and a solid unit. Why waste $$ on something that may or may not be accurate? Think about it.. WATER is the single largest component of your system... why risk it with a TOY when for just a few more dollars you can KNOW what your salinity is?


If you're still "Up in the air" about it then take about 2 minutes and read this article
Swing Arm Hydrometer Vs. Refractometer Vs. Floating Hydrometer - Tropical Fish Forums

 

[vsiege]

Thanks for all of your help. I thought those swing arms looked suspect. I am going to order the refractometer above.

 

[vsiege]

!!!!!!! It's out of stock. Any other suggestions?

 

[nanoreefing4fun]

Love my $59 one... so easy to read - I also have a F & S $49 one, but really like my Captive Purity one

Captive Purity Refractometer

 

[BigAl07]

Check out our sponsors sections as often times they have specials. If you dont find one there you can always go to
Dog health: veterinarian supplies: Portable Refractometer

 

[tnwillia]

This will keep you busy, some may already be listed above. Have fun!

Vertex Salinity Refractometer with ATC - AquaCave

Sybon Salinity Refractometer with ATC - AquaCave

Captive Purity Refractometer

Marine Depot Aquarium Pro Refractometer

Saltwater Aquarium Salinity & Specific Gravity Testing: Portable Refractometer

PetSolutions | Pet Supplies for All Pets Since 1950

Vital Sine Refractometer (High cost)

 

[sasquatch]

nothing wrong with a swing arm if you have refractometer to check it with.

 

[vsiege]

Ok, so I jumped over the swing arm and got my serious (ha). I ended up purchasing the Sybon Refractometer from here (actually have some good prices on other items as well). I will give an update once I get my tank up and cycling. Thanks foR ALL your help

 

[nanoreefing4fun]

You are very welcome ! Congrats on the new Sybon Refractometer !

 

[vsiege]

I'm looking forward to my new kaleidoscope. ha

 

[nanoreefing4fun]

 

[artpics]

i use the hydrometer for mixing salt then check it with the refactometer.

Simple accurate and quick.

 

[mojoreef]

There is a VERY accurate "Hydrometer" but IMHO not an accurate "Swing Arm" hydrometer.

Well they both have their limitations. SO on a swing arm one has to know that the material used in the actual arm is calibrated. Some are calibrated at 77F and some are calibrated at the 60F standard, so they can be accurate as long as you know the calibration standard and then the temperature corrections needed.

On the floating hydrometers it kind of falls into the same concept, you need to look at the part of the tube where it begins to widen (most cases) and it will tell you what temperature it has been calibrated at and if you are testing your water at the temp it has been done at then your ok, if not then you need to calculate your compensation?

On the refractometers this CAN also be the case, so make sure when you buy one that it has an automatic temp compensation. Typical good one will compensate temps between 50F and 86F if they dont then you will once again need to find a temp chart and make the adjustments manually.

Mojo