I've used the same Seatest hydrometer for 14 years. I just rinse it out with hot water once in
awhile. If I got another one to compare measurements, it would just complicate things.



"TheRock" wrote in message news:Xz2ig.8890$Rv1.4529@trndny02...
OK let me add my 2 cents...how accurate do you need salinity to be ?
If you shoot for the range that's indicated on the swing arm
and you keep an eye on your corals and other tank life.
It's safe to assume that you are where you need to be.

I have my best success by keeping the arm somewhere in the middle
usually to the high side. .022 .023 .024

How about replacing your Deep Six every other year, just
to make sure you have a functioning Hydrometer...(gunk build up, etc)
They're only $10

If the corals and fish look healthy I don't see the need for such high accuracy.
In other words, close enough.

Chris

"Susan" wrote in message .. .
I wouldn't be without a refractometer. I've used the swing arm ones and never could get the same reading twice. You can rest
assured, Cindy, if you are interested in buying from Dr Fosters or Premium Aquatics that both places are excellent place to buy
from!!! Also, Premium Aquatics has the best live rock (if anyone is interested) that I've run across. Not trying to start a
"rock war" again ;-)

Susan
"Pszemol" wrote in message ...
Try soaking both hydrometers for a day or two in kitchen vineger regularly.
Then wash it with warm water. This will dissolve deposits and make them more
reliable. I have also read on the back of the packaging that the manufacturer
recommends soaking it for at least 24 hours in sea water before
first use to "season the needle". I have no idea what science is
behind this recomendation, but maybe it is important fact you missed
comparing your old, dried out hygrometer readings with the other one.

From my own experience I prefer swing arms over refractometers by far!
Contrary to some people here I found them much easier to use than
to stare into tiny viewfinder and find the reading on very, very tiny scale
with an edge between blue and white regions being not always very sharp.
It might be some problem with my blue refractometer made in China
or some problems with my vision but I just find it very difficult to use :-)
With added uncertainity of most of them being calibrated to NaCl not NSW
they are not worth the price for the average aquarist. I can use Deep Six
hydrometer with good or bad light and I find them very reliable when
I wash them frequently and not let them dry with salt water in their cavity.