Do Hydrometers go bad

[cmack]

I have a floating type hydrometer that is approx 10 yrs old, and a new "Deep Six" swing needle type. The floating hydrometer currently reads 1.023 to 1.024, and the new swing needle reads 1.020.
it is a new 90 gal tank, and my goal was 1.022, and now I'm not sure if I am above or below that.

 

[surfnturf]

I just wanted to add that floating hydrometers are calibrated at somewhere around 70 degrees, so they will give inaccurate readings at normal SW temperatures(there are conversion charts out there). I would trust the deep six or whatever you have over the floating type. If you really want to be accurate, get a refractometer, they go for about $100 - 150, It's been a while since I looked at the price, but that's a ballpark anyway, HTH.

 

[cmack]

My current temperature is 78, so that could explain the inaccuracies, I'll trust the "Deep Six". Thanks for the help

 

[twoods71]

I dont have experience with the floating type but can tell you from experience with the swing arms they will go bad over time.
I recently purchased a refractometer and would highly recommend them to anyone. They are coming down in price to an affordable range. I got mine for $69.

 

[nacl-h2o]

Another thing that could through them off is deposits. You can fill it with white vinager and let it sit for a few hours or overnight to desolve the deposites. I have done this a few times to restore accuracy. If this is all that is wrong it is a very cheap fix. HTH

 

[josh]

Honeslty are the swing arm and float ever any good? They give you a ballpark value, if you don't want to shell out the bucks for a refractometer....which BTW are selling for 50 bucks now.....take some water into a LFS and have it tested there. Most LFS have a refractometer. Then just apply the correction value to what yours is reading.
just my two pennies

 

[madd catt]

Somebody here said that using a tooth brush to clean them works also for the swing arm type

 

[dburr]

I took my deep six right to the LFS and had them check it. It turns out i'm .0018 low on my reading. Now I just add that to what get.
Works out in the end.
Good luck