Do Hydrometers where out?

[808smokey]

I have an Instant Ocean Hydrometer that's about 5 years old.
I'm wondering how long do they last before they're not accurate?
Thanks

 

[fishmamma]

If in doubt take it to a good LFS and they can calibrate it and check it against theirs. I would think if you are still able to calibrate it it should continue to be accurate.

 

[jenn-e]

yes they wear out. Over time they get salt built up on them and it makes them read differently. I would test it against a refractometer. Or just buy a refractometer. Much more reliable.

 

[itchy]

Some say to soak the hydrometer in vinegar water. It will help remove salt build up.

 

[schadiest1]

i agree with Itchy.... cleaning it will help the accuracy of it's readings. white distilled vinegar will really help clean up salt build up. you should at least clean it with fresh water before each use.

 

[us~^>shark]

Mine was off by 0.5 from the beginning. Bought a refractometer instead. So I have a new Instant Ocean hydrometer but won't ever use it. By the way, how do they calibrate them? I don't see any way to adjust the arm?

 

[808smokey]

Well if I follow the directions off the bag of salt it says this:
Premix - 1/2 cup of salt mix for every gallon of water. Shake to disolve.
I do that and I'm up to almost two (2) full cups of salt and it's still only reading around 1.012-1.014. So something is definitly wrong. I can fill it with plane old tap water and it moves up a little bit. I clean it off the best I could but it's all screwy. I'll just get a new one.
Thanks for the help!

 

[acrylic51]

Originally Posted by fishmamma
If in doubt take it to a good LFS and they can calibrate it and check it against theirs. I would think if you are still able to calibrate it it should continue to be accurate.
How do they calibrate your swing arm hydrometer??? They aren't accurate and save your self a lot of headache and just buy a refractometer... You could go to you LFS and buy 3 of the same type or 3 different hydrometers and guess what you will get totally different readings....
Alot of people don't know but before the hydrometers are used they should be soaked to allow the plastic arms to absorb water. It does affect the readings you will get....

 

[ophiura]

There are a lot of potential issues with them. Mine was off (high) about 2 points on specific gravity (read 1.026 when it was basically 1.024). 1.024 was definitely not where I wanted it!! So I do recommend a refractometer. Having said that, I didn't ditch my hydrometer - still us it for quick readings now that I know where it is at. If you can, have it checked against a (properly calibrated) refractometer to give you a baseline...and do soak it frequently in white vinegar. But it may stil vary a lot. They are not really all that accurate.

 

[fishmamma]

My bad, I was having a brain freeze and thought you meant refractometer. I don't think you can calibrate a hydrometer. Mine was off like ophiura'sfrom the get-go, so I now also use a refractometer.