Specific gravity testing

[Blag It]

Hello,
Been reading up on equipment for marine setups.
I have a biorb and have purchased the marine kit.
I know I don't need any powerheads, protein skimmers, etc.
When it comes to the hydrometer, should this be replaced with a refractometer for a better reading? How unreliable are hydrometers?
Also if anyone has any suggestions for other items I should purchase, please let me know!
Thanks!

 

[cmor1701d]

Get a refractometer and never look back. If you are using a swing arm the problems are consistency and therefore accuracy. Very few people follow the directions to the T. A refractometer still needs to be calibrated, but it's rather easy. Many folks use a RODI water to calibrate 0, but I prefer getting a solution meant to calibrate at 35ppt (1.026 SG). It is usually sold as Salinity 53.0 mS Calibration Fluid.

 

[Blag It]

Calibration sounds complicated...

 

[cmor1701d]

Oh it is .
Put a few drops of fluid on the plate.
Look through the viewfinder to check the SG
Turn the set screw to adjust it to match the known value, if necessary

 

[EriksFish315]

Have someone who kows what there doing do it that's for sure.

 

[Blag It]

... I'm sure the fish guy at my lps will help! I hope!

 

[Blag It]

Gone for the needle hydrometer over the refractometer. Simply because of a huge difference in price! The needle is more accurate than the floating one so all good thanks guys!

 

[melosu58]

The hydrometer is no where near as accurate as the refractometer. I`ve seen folks here that there`s is off up to .005 . That`s a pretty big difference. It might have been cheaper but I promise you it is not as reliable.

 

[EriksFish315]

^^agreed Lfs here has refractometers for $50 well worth the investment. They also don't need replacing.

 

[cmor1701d]

I've seen ATC refractometers from $29 to $35 on eBay and the like. Some sponsors carry them in the $35 - $50 range. A six dollar swing arm is a problem. They are just not acdcurate.

 

[EriksFish315]

Not accurate at all seen it used and there terrible.

 

[cmor1701d]

A quality floating hydrometer would be much more accurate. Of course a quality lab grade hydrometer would be about half the cost of a refractometer and as it's made of glass it could break in the aquarium.

 

[EriksFish315]

I use a hydrometer it's accurate if your good at reading it I compared it to a refractometer and it's dead on.

 

[SeanMonster]

I use a hydrometer it's accurate if your good at reading it I compared it to a refractometer and it's dead on.

My hydrometer is dead-on with my lfs owner's refractometer. I usually just make sure that I don't introduce air bubbles to the arm hen I take a reading.

 

[EriksFish315]

Yeah I like the floating one I use.

 

[SeanMonster]

I've also found rinsing it with fresh water after use prevents salt residue from building up inside of it.

 

[cmor1701d]

Rinsing in freshwater is an absolute must for the swing arm hydrometers. However, try testing 3 times in a half hour and tell me what readings you get. I found they are not consistent and therefore unreliable.

I calibrate my refractometer once every few months, or if I think a reading may be off. It takes under a minute to check it and I know it's accurate. Stable SG is one of the most important parameters to maintain. For the few extra dollars on a device that lasts seemingly forever is well worth it.

 

[Convict2161]

Thanks to this thread I'll be buying a refractometer over the weekend whether online or in store but I'm getting one.

Thanks for the thread.

 

[Blag It]

My floating hydrometer is awkward to read. The swing arm is fine if rinsed with freshwater and no bubbles are in it. Considering my tank is rather small, doesn't contain live corals, and will only have a few inhabitants, it will do just fine. I am however planning on purchasing a refractometer, but only when I can afford to do so. Thanks for the shared info guys.

 

[EriksFish315]

Yeah all the info and knowledge you can acquire is helpful.