Instant Ocean Hydrometer

[Sarah Navarro]

Has anyone else noticed that this brand always gives a higher salinity
reading than other brands? I have one Deep Six brand, two Sealtest, and one
Instant Ocean, this one is always higher, by quite a bit than the other
ones. My friend also has an Instant Ocean and I tried it and it tests
higher also.

Sarah

[CheezWiz]

You really should get one of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=20755&item=4378279657&rd=1

Calibrates to 0 with RO/DI and direct reads salinity
Just to be sure to get one that is temperature compensated.

CW
"Sarah Navarro" > wrote in message
ink.net...
> Has anyone else noticed that this brand always gives a higher salinity
> reading than other brands? I have one Deep Six brand, two Sealtest, and
> one Instant Ocean, this one is always higher, by quite a bit than the
> other ones. My friend also has an Instant Ocean and I tried it and it
> tests higher also.
>
> Sarah
>

[Pszemol]

"Sarah Navarro" > wrote in message ink.net...
> is always higher, by quite a bit than the other ones.

how much higher ?

[George]

"Pszemol" > wrote in message
...
> "Sarah Navarro" > wrote in message
> ink.net...
>> is always higher, by quite a bit than the other ones.
>
> how much higher ?

I have one of those and I've noticed that is reads about 0.02 higher than the
one I used to have (an older model of the same brand). I noticed this the first
time I used it. My solution was to keep the salinity in the middle of the
acceptible range.

[Pszemol]

"George" > wrote in message news:PFSee.61123$WI3.8521@attbi_s71...
> "Pszemol" > wrote in message
> ...
>> "Sarah Navarro" > wrote in message
>> ink.net...
>>> is always higher, by quite a bit than the other ones.
>>
>> how much higher ?
>
> I have one of those and I've noticed that is reads about 0.02 higher than the
> one I used to have (an older model of the same brand). I noticed this the first
> time I used it. My solution was to keep the salinity in the middle of the
> acceptible range.

Hm... So instead of 1.023 it read 1.043 ???? And you kept at 1.033 ?

BTW - The good idea is to keep them clean - when there is some salt
deposit inside it will interfere with the reading. I soak mine in
hot water from time to time and do not see anything wrong with them.

[Sarah Navarro]

I always rinse mine in fresh water afterward because that what it says to
do. I still don't understand why it reads higher than other brands though.
Have you ever tried yours against another brand at the same time? Just
curious.

Sarah

"Pszemol" > wrote in message
...
>
> BTW - The good idea is to keep them clean - when there is some salt
> deposit inside it will interfere with the reading. I soak mine in
> hot water from time to time and do not see anything wrong with them.

[Benjamin]

I thought someone much wiser than I said to rinse them in RO or RO/DI water
after use then seal them up in a Ziploc and keep in a dark place for utmost
accuracy. After finding out where the right reading is by first comparing
them against a refractometer of course, then checking that comparison
periodically.
Might be overkill, then again might not be.

--
--
--




"Sarah Navarro" > wrote in message
ink.net...
>I always rinse mine in fresh water afterward because that what it says to
>do. I still don't understand why it reads higher than other brands though.
>Have you ever tried yours against another brand at the same time? Just
>curious.
>
> Sarah
>
> "Pszemol" > wrote in message
> ...
>>
>> BTW - The good idea is to keep them clean - when there is some salt
>> deposit inside it will interfere with the reading. I soak mine in
>> hot water from time to time and do not see anything wrong with them.
>
>

[Pszemol]

"Sarah Navarro" > wrote in message ink.net...
> I always rinse mine in fresh water afterward because that what it says to
> do. I still don't understand why it reads higher than other brands though.
> Have you ever tried yours against another brand at the same time? Just
> curious.

Could you please answer my question: how much higher readings do you get?

[Rikko]

On Thu, 05 May 2005 04:21:01 GMT, "Sarah Navarro"
> wrote:

>Has anyone else noticed that this brand always gives a higher salinity
>reading than other brands? I have one Deep Six brand, two Sealtest, and one
>Instant Ocean, this one is always higher, by quite a bit than the other
>ones. My friend also has an Instant Ocean and I tried it and it tests
>higher also.
>
>Sarah

I've tested 2 of the Instant Ocean ones and a couple of the cheap-o
Hagen floating hydrometers against my refractometer and they've all
been dead on.

[George]

"Pszemol" > wrote in message
...
> "George" > wrote in message
> news:PFSee.61123$WI3.8521@attbi_s71...
>> "Pszemol" > wrote in message
>> ...
>>> "Sarah Navarro" > wrote in message
>>> ink.net...
>>>> is always higher, by quite a bit than the other ones.
>>>
>>> how much higher ?
>>
>> I have one of those and I've noticed that is reads about 0.02 higher than
>> the one I used to have (an older model of the same brand). I noticed this
>> the first time I used it. My solution was to keep the salinity in the middle
>> of the acceptible range.
>
> Hm... So instead of 1.023 it read 1.043 ???? And you kept at 1.033 ?
>
> BTW - The good idea is to keep them clean - when there is some salt
> deposit inside it will interfere with the reading. I soak mine in
> hot water from time to time and do not see anything wrong with them.

Oops. Make that 0.002, not 0.02. Sorry. I always clean them.

[George]

"Rikko" > wrote in message
...
> On Thu, 05 May 2005 04:21:01 GMT, "Sarah Navarro"
> > wrote:
>
>>Has anyone else noticed that this brand always gives a higher salinity
>>reading than other brands? I have one Deep Six brand, two Sealtest, and one
>>Instant Ocean, this one is always higher, by quite a bit than the other
>>ones. My friend also has an Instant Ocean and I tried it and it tests
>>higher also.
>>
>>Sarah
>
> I've tested 2 of the Instant Ocean ones and a couple of the cheap-o
> Hagen floating hydrometers against my refractometer and they've all
> been dead on.

Hmmm. Maybe it was my old Instant ocean hydrometer which was giving false
readings. This warrants further investigation. I'll get back to you.

[[email protected]]

I found mine to be 0.002 higher than a calibrated refractometer. So I bought
a refractometer! Just make sure you are checking the temperature. My
refractometer is not temperature compensated so you can expect about 0.001
difference between room temp. and tamk temp.

Regards

Mark

[Pszemol]

> wrote in message ...
> I found mine to be 0.002 higher than a calibrated refractometer. So I bought
> a refractometer! Just make sure you are checking the temperature. My
> refractometer is not temperature compensated so you can expect about 0.001
> difference between room temp. and tamk temp.

Is it sea-water refractometer or just NaCl calibrated?

[Tre' Landrum]

I didn't know there was any difference? I thought it was just based on
what's dissolved in the water (NaCl, KCl, or another mineral). Is this the
difference in a cheap refractometer? I have seen some in the $50 range, but
am always leery of the deal that is too good to be true. If this isn't the
difference what is? Thanks!

Tre'

> Is it sea-water refractometer or just NaCl calibrated?

[Pszemol]

"Tre' Landrum" > wrote in message news:zLhfe.895$Db6.770@okepread05...
> I didn't know there was any difference? I thought it was just based on
> what's dissolved in the water (NaCl, KCl, or another mineral). Is this the
> difference in a cheap refractometer? I have seen some in the $50 range, but
> am always leery of the deal that is too good to be true. If this isn't the
> difference what is? Thanks!

Of course there is a difference. Refraction of light depends on
what is in the water. There are many different refractometers
used to measure brine (NaCL), sugar and other stuff...
I do not remember what is the correction to be used between
NaCl refractometer and sea water, but these are not the same.

[[email protected]]

This is a seawater refractometer that measures salinity and specific
gravity. Obviously other elements have an effect, but then they do with a
hydrometer.

Mark

[Pszemol]

> wrote in message ...
> This is a seawater refractometer that measures salinity and specific
> gravity.

What manufacturer & model # ? I am on the market for one like this.

[[email protected]]

It's a Deltec RHS-10 (without automatic temperature compensation) is
measures 0-100 PPT (+ or - 1.0 PPT) salinity and 1.000 to 1.070 (+ or -
0.001) specific gravity.

Deltec also do a version with automatic temperature compensation with the
model number RHS-10ATC (strangely enough!).

To be honest, I think is only badged as Deltec (there is a sticky label on
the box) I don't know who actually makes it. ISTR is cost about 40 UK
Pounds. As with most things that probably means it would cost about 40 US $
(we always seem to pay over the odds for things here!).

Regards

Mark

[Pszemol]

> wrote in message ...
> It's a Deltec RHS-10 (without automatic temperature compensation) is
> measures 0-100 PPT (+ or - 1.0 PPT) salinity and 1.000 to 1.070 (+ or -
> 0.001) specific gravity.
>
> Deltec also do a version with automatic temperature compensation with the
> model number RHS-10ATC (strangely enough!).
>
> To be honest, I think is only badged as Deltec (there is a sticky label on
> the box) I don't know who actually makes it. ISTR is cost about 40 UK
> Pounds. As with most things that probably means it would cost about 40 US $
> (we always seem to pay over the odds for things here!).

I remember reading somewhere that regular brine refractometers
are introducing some error in measuring seawater, but I cannot
find this article or I do not remember how big the error is.

Yours looks like "generic" RHS-10 refractometer which is not
made by Deltec. And its being not ATC you need to make sure
that the temperature of ambient air cooling down refractometer
to 20'C/70F can influence of reading density of your tank water
which was 78-80F but was cooled down to the room temperature
when you drip couple of drops on the refractometer's prism.
If you had ATC version you could probably ignore temperature factor.

[Aquacare]

Greetings,

I currently use many brands of salinity meters. The best one so far is the
refractometer. The plastic units should all be calibrated against a good
quality refractometer or a nice glass floating hydrometer. I have not sold
or used one yet that wasn't off just a little. By a little i mean .001-.003.
I have seen some over the years that were really off. !!

[[email protected]]

Yes, that's true. You have to give the water in the refractometer a minute
to stabilise to the refractometer temperature (room temp) and then make the
allowance. On average, it works out to be about 0.001 different from the
actual reading. An ATC model would be nice.

Mark

[[email protected]]

I calibrate mine using distilled water (obviously to 1.000). Are you saying
that there is an anomoly (above the quoted + or - 0.001 accuracy) after
calibration when you measure seawater?

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[Aquacare]

After they are calibrated they work well.

[Boomer]

Mark

A refract is off " - 15" units, right out of the box.

99.99 % of all refractrs, we would use in the hobby, are calibrated to NaCl Salinity.
Salinity does not mean seawater salinity, it could be KCl, NaCl Salinity etc.. It is the
salinity of any "salt". Seawater Salinity is not the same as NaCl Salinity or KCl
Salinity, each has its own RI (Refractive Index). In other words, a 35 ppt NaCl RI is not
the same as a 35 ppt RI for KCl or Seawater. In order to calibrate a refract to NSW you
would want a sample that had the same RI as seawater. So, that would be a sample of
seawater that is know to be 35 ppt or to mathematically calculate a salinity using another
salt that would = NSW. Such is the case with the 3.65 % NaCl, which = NSW @ 3.5 %
Salinity. So, what is a" - 15 " unit ? It means the refract is reading an SG of .0015 to
low, .15 % to low or 1.5 ppt to low. So, for the refract for SG, you would want it to read
...1.0265 SG + .0015 SG = 1.028SG = NSW. SG............FOR %, 3.5 % + .15 % = 3.65 % NSW
%......... FOR ppt, 35ppt + 1.5ppt = 36.5ppt = NSW ppt

--
Boomer

Want to talk chemistry ? The Reef Chemistry Forum
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Former US Army Bomb Technician (EOD)
Member; IABTI, NATEODA, WEODF, ISEE & IPS

If You See Me Running You Better Catch-Up


> wrote in message ...
: Yes, that's true. You have to give the water in the refractometer a minute
: to stabilise to the refractometer temperature (room temp) and then make the
: allowance. On average, it works out to be about 0.001 different from the
: actual reading. An ATC model would be nice.
:
: Mark

[Pszemol]

"Boomer" > wrote in message ...
> A refract is off " - 15" units, right out of the box.
>
> 99.99 % of all refractrs, we would use in the hobby, are calibrated to NaCl Salinity.
> Salinity does not mean seawater salinity, it could be KCl, NaCl Salinity etc.. It is the
> salinity of any "salt". Seawater Salinity is not the same as NaCl Salinity or KCl
> Salinity, each has its own RI (Refractive Index). In other words, a 35 ppt NaCl RI is not
> the same as a 35 ppt RI for KCl or Seawater. In order to calibrate a refract to NSW you
> would want a sample that had the same RI as seawater. So, that would be a sample of
> seawater that is know to be 35 ppt or to mathematically calculate a salinity using another
> salt that would = NSW. Such is the case with the 3.65 % NaCl, which = NSW @ 3.5 %
> Salinity. So, what is a" - 15 " unit ? It means the refract is reading an SG of .0015 to
> low, .15 % to low or 1.5 ppt to low. So, for the refract for SG, you would want it to read
> ..1.0265 SG + .0015 SG = 1.028SG = NSW. SG............FOR %, 3.5 % + .15 % = 3.65 % NSW
> %......... FOR ppt, 35ppt + 1.5ppt = 36.5ppt = NSW ppt


Thanks - this was what I was missing :-)
But you rather keep reef tank at 35ppt not 36.5ppt, right ?
So you would want your refractometer to read 33.5ppt to have 35ppt NSW.
Am I correct ?

[[email protected]]

Thanks,

The pre-amble on mine says "is used in oceanography and seawater studies"
but then it also says "In the food industry it is especialy effective in the
preparation of frozen vegitables, fruits, seafood and ocean byproducts" - so
I suppose it is anyones guess, although 'oceanography sand seawater studies'
sounds promising!

Mark

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[Boomer]

PZE

"But you rather keep reef tank at 35ppt not 36.5ppt, right ?
So you would want your refractometer to read 33.5ppt to have 35ppt NSW.
Am I correct ?"


No PZE, you want to keep the tank at 36.5 as the refract is in error 1.5 . 36.5 ppt Sodium
Chloride Salinity = 35 ppt NSW Salinity. Now what you can do is once the refract reads
36.5, turn the calibration screw on it till it reads 35 ppt, no you are set for NSW

--
Boomer

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Former US Army Bomb Technician (EOD)
Member; IABTI, NATEODA, WEODF, ISEE & IPS

If You See Me Running You Better Catch-Up


"Pszemol" > wrote in message ...
: "Boomer" > wrote in message
...
: > A refract is off " - 15" units, right out of the box.
: >
: > 99.99 % of all refractrs, we would use in the hobby, are calibrated to NaCl Salinity.
: > Salinity does not mean seawater salinity, it could be KCl, NaCl Salinity etc.. It is
the
: > salinity of any "salt". Seawater Salinity is not the same as NaCl Salinity or KCl
: > Salinity, each has its own RI (Refractive Index). In other words, a 35 ppt NaCl RI is
not
: > the same as a 35 ppt RI for KCl or Seawater. In order to calibrate a refract to NSW
you
: > would want a sample that had the same RI as seawater. So, that would be a sample of
: > seawater that is know to be 35 ppt or to mathematically calculate a salinity using
another
: > salt that would = NSW. Such is the case with the 3.65 % NaCl, which = NSW @ 3.5 %
: > Salinity. So, what is a" - 15 " unit ? It means the refract is reading an SG of .0015
to
: > low, .15 % to low or 1.5 ppt to low. So, for the refract for SG, you would want it to
read
: > ..1.0265 SG + .0015 SG = 1.028SG = NSW. SG............FOR %, 3.5 % + .15 % = 3.65 %
NSW
: > %......... FOR ppt, 35ppt + 1.5ppt = 36.5ppt = NSW ppt
:
:
: Thanks - this was what I was missing :-)
: But you rather keep reef tank at 35ppt not 36.5ppt, right ?
: So you would want your refractometer to read 33.5ppt to have 35ppt NSW.
: Am I correct ?

[Boomer]

I know Mark the try to BS you. There is only one company in the world that I know of that
sells a refract calibrated to NSW, for the tune of about $600. You have the most common
refract there is in this hobby, it is made in China the RHS-10ATC . Here is the real
maker.

http://www.instrument-china.com/index.htm This page has an error so click on RHS-10,
which has both.


Although many of the companies that make these may say what you posted it is BS. They are
calibrated from the factory and you can't calibrate a refract to sodium chloride salinity
and NSW salinity at the same time, as NSW has a higher RI (Refractive Index). These
companies are also not going to be giving you seawater NIST STD, which cost more than your
refract by a factor of over 5. :-)


--
Boomer

Want to talk chemistry ? The Reef Chemistry Forum
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Former US Army Bomb Technician (EOD)
Member; IABTI, NATEODA, WEODF, ISEE & IPS

If You See Me Running You Better Catch-Up


> wrote in message
...
: Thanks,
:
: The pre-amble on mine says "is used in oceanography and seawater studies"
: but then it also says "In the food industry it is especialy effective in the
: preparation of frozen vegitables, fruits, seafood and ocean byproducts" - so
: I suppose it is anyones guess, although 'oceanography sand seawater studies'
: sounds promising!
:
: Mark
:
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[Pszemol]

Ok, thanks, I got it backward somehow :-)

"Boomer" > wrote in message ...
> PZE
>
> "But you rather keep reef tank at 35ppt not 36.5ppt, right ?
> So you would want your refractometer to read 33.5ppt to have 35ppt NSW.
> Am I correct ?"
>
>
> No PZE, you want to keep the tank at 36.5 as the refract is in error 1.5 . 36.5 ppt Sodium
> Chloride Salinity = 35 ppt NSW Salinity. Now what you can do is once the refract reads
> 36.5, turn the calibration screw on it till it reads 35 ppt, no you are set for NSW

[[email protected]]

Thanks, that's useful. More compensation required!

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[Chip]

For 30 bucks more a good refratometer can be had. You can find those
swingarm hydrometers to be off even if they set on a surface that is
not perfectly level, or if the temp is different, or they get a micro
bubble on the arm, or if the arm happens to be a bit stiff if it wa
not cleaned after use.....Refractometers are just to readily available
and cheap to buy. At the least a reputable lfs "shold" have a
refractometer, and it wold be reasonable in my mindset to have them
check your swingarm type no matter who makes it for accuaracy, if for
nothig else than piece of mind. My Instant Ocean was showing a 1.023
reading but whenn bumped up against refractometer the water actually
was a 1.021..........so Now that I know what it reads, I can also
check it to see where it reads with water of known SG, but its just so
much easier to use a refractometer.

On Thu, 05 May 2005 04:21:01 GMT, "Sarah Navarro"
> wrote:

>===<>Has anyone else noticed that this brand always gives a higher salinity
>===<>reading than other brands? I have one Deep Six brand, two Sealtest, and one
>===<>Instant Ocean, this one is always higher, by quite a bit than the other
>===<>ones. My friend also has an Instant Ocean and I tried it and it tests
>===<>higher also.
>===<>
>===<>Sarah
>===<>


==============================================
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