Hydrometer question

brandon4432 · 08/22/2015, 12:22 PM

I'm aware that hydrometers are looked down upon in the hobby and refractometers are the way to go but if using a hydrometer how accurate are they at 80 degrees?

billdogg · 08/22/2015, 01:06 PM

Although they may not be "dead on", it is easy enough to calibrate them with a known source. As long as you rinse them well and look carefully for air bubbles you will be fine.

Consistency is at least as important as the actual number, IMO.

kfisc · 08/22/2015, 03:47 PM

Be aware that refractometers are no more accurate than their last calibration. They can also age poorly: coatings peel off, screws rust and so on. Hydrometers calibrated to a good reference are just as good.

ericarenee · 08/22/2015, 04:18 PM

Quote:

Originally Posted by kfisc

be aware that refractometers are no more accurate than their last calibration. They can also age poorly: Coatings peel off, screws rust and so on. Hydrometers calibrated to a good reference are just as good.

1+

Ron Reefman · 08/23/2015, 10:35 AM

I have a hydrometer that I 'calibrated' with a freshly calibrated refractometer. The hydrometer read 0.004 too low. So I labeled it with that info. It's been in use for years and every time I re-calibrate my refractometer (every 6 to 9 months) I compare readings with the hydrometer again. Many years on and the hydrometer is still 0.004 too low.

Every hydrometer is different. Just get it compared to a good refractometer and label it. After that, keep it clean and watch for bubbles on the swing arm. As billdogg said, consistency is as important as an exact reading. I hardly ever use my refractometer.

JMorris271 · 08/23/2015, 02:05 PM

Milwaukee MA $ 140
generic hydrometer $12.

The $140 refractometer must be better. Hmmmmmm
FTR I have both.

Ron Reefman · 08/23/2015, 05:48 PM

Quote:

Originally Posted by JMorris271

Milwaukee MA $ 140
generic hydrometer $12.

The $140 refractometer must be better. Hmmmmmm
FTR I have both.

Probably not if you know what you are doing. But it sure helps you spend money faster!

JMorris271 · 08/23/2015, 06:42 PM

Quote:

Originally Posted by Ron Reefman

Probably not if you know what you are doing. But it sure helps you spend money faster!

Was playing devil's advocate there.

nuxx · 08/24/2015, 02:37 PM

Had a hydrometer that was on for years... then just stopped working right.

Bought a new one and was off after a week.

Just buy a refractometer and calibrate it every few months.

CStrickland · 08/24/2015, 02:56 PM

Quote:

Originally Posted by brandon4432

I'm aware that hydrometers are looked down upon in the hobby and refractometers are the way to go but if using a hydrometer how accurate are they at 80 degrees?

A lot of people don't prime the needle. I let mine sit wet for a few minutes then dump it out and test the water. Idk, just an old wives tale I read somewhere but mine works fine. I check it against a better one every once in a while and so far so good. I also soak a few hours in vinegar now and then. I don't think the temp matters like it does for the refractometers and tds meters and other digital checkers

08/22/2015, 12:22 PM	#1
brandon4432 Registered Member Join Date: Jul 2015 Posts: 9	Hydrometer question I'm aware that hydrometers are looked down upon in the hobby and refractometers are the way to go but if using a hydrometer how accurate are they at 80 degrees?

08/22/2015, 01:06 PM	#2
billdogg Registered Member Join Date: Apr 2008 Location: Grove City, Ohio Posts: 10,806	Although they may not be "dead on", it is easy enough to calibrate them with a known source. As long as you rinse them well and look carefully for air bubbles you will be fine. Consistency is at least as important as the actual number, IMO. __________________ I'll try to be nice if you try to be smarter! I can't help that I grow older, but you can't make me grow up! Current Tank Info: 120 mixed reef with 40b sump, RO 150 skimmer, AI Sol Blue x 2, and a 60g Frag Tank with 100g rubbermaid sump. 2 x Kessil A360w lights, BM curve 5 skimmer

08/23/2015, 10:35 AM	#5
Ron Reefman Registered Member Join Date: Jul 2009 Location: Cape Coral, FL Posts: 10,431	I have a hydrometer that I 'calibrated' with a freshly calibrated refractometer. The hydrometer read 0.004 too low. So I labeled it with that info. It's been in use for years and every time I re-calibrate my refractometer (every 6 to 9 months) I compare readings with the hydrometer again. Many years on and the hydrometer is still 0.004 too low. Every hydrometer is different. Just get it compared to a good refractometer and label it. After that, keep it clean and watch for bubbles on the swing arm. As billdogg said, consistency is as important as an exact reading. I hardly ever use my refractometer. __________________ The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson) Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017

08/23/2015, 02:05 PM	#6
JMorris271 Registered Member Join Date: Feb 2014 Location: Foothills of SC Posts: 2,010	Milwaukee MA $ 140 generic hydrometer $12. The $140 refractometer must be better. Hmmmmmm FTR I have both. __________________ 120 gal mixed tank. Lightly stocked now but....

08/24/2015, 02:37 PM	#9
nuxx RC Sponsor Join Date: Jan 2014 Location: Austin, Tx Posts: 3,990	Had a hydrometer that was on for years... then just stopped working right. Bought a new one and was off after a week. Just buy a refractometer and calibrate it every few months. __________________ Peter TankStop - Fish and Coral 470G Display - Build Thread Current Tank Info: Retired - 470 Gallon Mixed Reef (120x29x31")

08/22/2015, 03:47 PM	#3
kfisc Registered Member Join Date: Nov 2003 Posts: 2,020	Be aware that refractometers are no more accurate than their last calibration. They can also age poorly: coatings peel off, screws rust and so on. Hydrometers calibrated to a good reference are just as good.