# Refractometer or Hydrometer ?



## Ice (Sep 25, 2006)

What's the difference between the Refractometer and the Hydrometer ? Don't they both do the same type of measurement/calibrations of determining accurate reading on salinity or specific gravity ? Do you recommend having both or one over the other ?


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## Guest (Dec 2, 2006)

refractometers measure the percent of salt in the water whereas hydrometers measure the specific gravity of the water (the effect that salt has on water).
i personally use a hydrometer, although others say refractometers are far more precise. Im not really 100% on that, i still think that hydrometers are pretty precise, or only slightly off or less precise than a refractometer. However, they are a fraction of the cost. I prefer a hydrometer and i know others will disagree and say a refractometer is much much better, so i guess if you have the extra dough go for it. Otherwise, i don't see a problem with a decent hydrometer.


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## Bear (Jun 8, 2006)

^^I agree, I would just stick with the hydrometer


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## vvolfe1 (Oct 9, 2006)

I'm using a hydrometer. It has a dual purpose when I make beer.


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## harif87 (Jun 5, 2006)

Some say that it doesnt account for the change in high tempertatures and that over time the needle hinge gets clogged with salt and gives less than accurate readings. Personally i use a refractometer since i feel like hydrometers are more prone to inaccurate readings than a refractometer. Refractometers go for around $35 and IMO its worth every penny.


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## CollegeReefer (Sep 1, 2006)

Ice i would get a Refractometer. Actually i would get the refractometer Harif mentioned. They are much more accurate. I know this from experience. I have both. The hydrometer was different by .03 and if you look at other peoples opinons on different sites you will see similar stories. 

Zachary


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## Ice (Sep 25, 2006)

Thanks for the replies. Now I'll know what to put on my list.


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## Fishfirst (Jan 24, 2005)

I've had my hydrometer for years... its off by about .05 

the longer you use it... the farther off it gets.


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## aykfc (Jun 6, 2006)

Harif, where did you get your refractometer? I was at a LFS and they had a really good one for $90 and all my research said they were around $100. I have a cheap hydrometer right now that measures somewhat precise and was looking at getting a refractometer. Any suggestions?


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## Damon (Jan 18, 2005)

If you have the extra cash, get a refractometer. A hydrometer will work well enough for you as it has many for years and years.....


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## harif87 (Jun 5, 2006)

I got mine from marine depot. Dont go for the $90 one, its not worth it. All it has over the "lower end" ones is that it has a light to see the reading better, so they jack up the price an extra $40. I would go for the $50 IMHO its well worth the money spent- better than the $90 refractometer and better than the $5 hydrometer.


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## Puffer Pita (Jun 16, 2006)

Got mine for $25 on Ebay. Tons of brand new ones on sale.


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## fishbone (Jan 15, 2007)

Topic revival time! Better than to open a new one on the exact same topic.
So I currently have an Instant Ocean brand hydrometer but for my brackish set-up it's hard to read. Basically the gravity down low is marked from 1.004 up to 1.008 so it's hard to tell what's in between.
I've decided to invest into a refractometer off eBay but I'm affraid to buy a cheap knock-off that will cause harm to my set-up
Here's a random search result
http://search.ebay.com/search/searc...kr=1&from=R8&satitle=refractometer&category0=
There's a bunch going for 10-20 bucks, kinda like the one here:
http://cgi.ebay.com/Salinity-Salt-R...0QQihZ002QQcategoryZ11876QQrdZ1QQcmdZViewItem
Are these ok? What should I look out for?


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## Puffer Pita (Jun 16, 2006)

Make sure its clearly marked to read salinity from 0-100 and/or a specific gravity of 1.000-1.070. Also make sure its an ATC.

This is the guy I get mine from and I highly recommend him: http://stores.ebay.com/OPTICS-MART


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## (RC) (Jan 18, 2005)

I would go
Refractometer Reef Tank
Hydrometer Fish Only Tank I used one for my "Fish" tank


RC


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## fishbone (Jan 15, 2007)

Puffer Pita, I am ordering now. Thanks a TON, that's exactly what I was looking for, a name of a seller so I know it won't be a deadbeat.
What sort of maintenance do these things require?


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## Puffer Pita (Jun 16, 2006)

A quick rinse of the glass and cover with distilled water. Just make sure to get some spare pipettes (cheap at the drugstore) and use one only for the salted water and one only for the distilled (distilled is also used to calibrate them - 1g jug of distilled water will last you ages and is under a buck). I marked my pipettes with a D and S.  Make sure you use a non-scratching type cloth to wipe it off, something like you would use to clean your eyeglasses.

He's a very good seller IMO, I received it 9 days after the auction ended and he left me good feedback right after I paid him, rather than waiting until I gave him good feedback like so many others do.


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## fishbone (Jan 15, 2007)

This toy will help me immensely, I do my best to not make the brackish water vary in gravity when I do my daily water changes, but the darn hydrometer is so hard to read. If I had a regular saltwater aquarium it would have been easier, as it is clearly marked in .001 increments. Not so much down low ...


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## kastotrin (Feb 20, 2007)

hydrometers are too hard to read....definetly go with the refractometer...i paid $40 for mine on ebay....one of the best investments ive made for my tank....


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