Hydrometer Accuracy and Cautions - Reef-Geeks

high tide · Big-Geek

If you have a swing arm style hydrometer and haven't yet purchased a refractometer there are a couple of things to be aware of. Each and every time a swing arm is used it acquires an accumulation of chemicals, this changes the weight of the swing arm thus changing the accuracy, a really good rinse with water will help but not stop this so over time they get worse.
Plastic is hygroscopic as in it absorbs water this means a brand new hyrdometer will provide a slightly different reading after the first few uses.
The biggest concern is air bubbles stuck to the swing arm, be sure to flick or tap the body several time to shake these off.
Where possible take your hydrometer to an LFS that has a refractometer and ask them to confirm the reading you get, as it cannot be adjusted you can make an educated guess.
When the price and convenience of a refractometer is considered it really is a very good investment.

shmoliken · Big-Geek

however, refracto's need to be calibrated accurately to be considered right. and they need a calibration at both zero and at a known seawater.
Refractometers and Salinity Measurement by Randy Holmes-Farley - Reefkeeping.com

Sneezy · Big-Geek

Great info Steve and Paul!

inlander · Big-Geek

A qick wash of a swing arm type throught the DW will help keep it accurate.

JMO

GHOGAN77 · Newbie-Geek

most coolfrags cost more!!
We're Sorry. . . The page you requested is no longer available

GHOGAN77 · Newbie-Geek

Saltwater Aquarium Salinity & Specific Gravity Testing: Portable Refractometer

[1 (permalink)] Posted by high tide 08-17-2010, 08:09 PM	Big-Geek
Hydrometer Accuracy and Cautions If you have a swing arm style hydrometer and haven't yet purchased a refractometer there are a couple of things to be aware of. Each and every time a swing arm is used it acquires an accumulation of chemicals, this changes the weight of the swing arm thus changing the accuracy, a really good rinse with water will help but not stop this so over time they get worse. Plastic is hygroscopic as in it absorbs water this means a brand new hyrdometer will provide a slightly different reading after the first few uses. The biggest concern is air bubbles stuck to the swing arm, be sure to flick or tap the body several time to shake these off. Where possible take your hydrometer to an LFS that has a refractometer and ask them to confirm the reading you get, as it cannot be adjusted you can make an educated guess. When the price and convenience of a refractometer is considered it really is a very good investment.	Join Date: Dec 2009 Posts: 5,338 Gameroom cash: $1517033 Rep Power: 89
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[2 (permalink)] Posted by shmoliken 08-18-2010, 05:52 AM	Big-Geek
however, refracto's need to be calibrated accurately to be considered right. and they need a calibration at both zero and at a known seawater. Refractometers and Salinity Measurement by Randy Holmes-Farley - Reefkeeping.com __________________ who knew salt water was made of $100 bills?	Join Date: Sep 2009 Location: de Posts: 1,492 Gameroom cash: $804220 Rep Power: 29
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[3 (permalink)] Posted by Sneezy 08-28-2010, 02:24 AM	Big-Geek
Great info Steve and Paul!	Join Date: Sep 2009 Posts: 9,197 Gameroom cash: $66 Rep Power: 116
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[4 (permalink)] Posted by inlander 08-30-2010, 03:20 PM	Big-Geek
A qick wash of a swing arm type throught the DW will help keep it accurate. JMO	Join Date: Jan 2010 Posts: 1,743 Gameroom cash: $509710 Rep Power: 58
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[5 (permalink)] Posted by GHOGAN77 01-03-2011, 09:49 PM	Newbie-Geek
really? most coolfrags cost more!! We're Sorry. . . The page you requested is no longer available	Join Date: Dec 2010 Location: Jax,Fl Posts: 49 Gameroom cash: $18950 Rep Power: 6
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[6 (permalink)] Posted by GHOGAN77 01-03-2011, 09:50 PM	Newbie-Geek
Saltwater Aquarium Salinity & Specific Gravity Testing: Portable Refractometer	Join Date: Dec 2010 Location: Jax,Fl Posts: 49 Gameroom cash: $18950 Rep Power: 6
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