Xplain, PPT to SRG no way to convert apples to apples ?

[Myka]

I have ordered for some 200 dollars a new refractometer made by True Sine and calibration fluid for it made by True Sine.

You could have spent less than $100 on either a D-D or Red Sea refractometer. Both of which are "true seawater" refractometers.

 

[Terence]

Here is what I do (and this is by no means official) - I adjust and check my water with two refractometers (one D-D and one no-name) that have been calibrated with Accurasea. Once I get it to what is a perfect 35 for me, I then use my tank as the high (53,000us) "solution". Done.

 

[Randy Holmes-Farley]

Here is what I do (and this is by no means official) - I adjust and check my water with two refractometers (one D-D and one no-name) that have been calibrated with Accurasea. Once I get it to what is a perfect 35 for me, I then use my tank as the high (53,000us) "solution". Done.

Well, at least they will always agree then.

 

[Terence]

Exactly. My point is simply that if I trust my two refractometers, and I trust my calibration solutions for those refractometers, all I really want is a digital representation of what I see there. And everything aligns.

 

[Terence]

Oh, also, there are many things that electrically interfere with conductivity probes. If they are constant, my way takes that into account.

 

[jason2459]

What the Apex salinity probe is reporting and what the refractometer is showing in my case is very very different. The probe is report near 44 and the refractometer is at 1.025.

APEX has no particular answer. Answers seems be you should not expect it. If I misunderstood Apex, I apolgize in advance and promise to drink a cup of tank water as atonement.

So.

I have ordered for some 200 dollars a new refractometer made by True Sine and calibration fluid for it made by True Sine.
Because I am given to understand my regular refracrometer only measures the brine content of the water but this one actually measures correctly. Not really sure why that is but....

I have ordered calibration fluid from Apex for the Apex probe and have discovered that someplace in advanced setting there is a place to let the probe know what the water temp. is. Why the probe is not smart enough to ask the temp. probe is beyound me. Seems a 1200 dollar controller would be able to do that. But ok.

When everything is here and recalibrated I will post the results of my enquiry.

I am posting two screen shots of my experience thus far.

Do you have a link to this True Sine refractometer? If it's a vital sine refractometer it is a very good refractometer that's actually made by Veegee and should be closer to $100. DD H2Ocean also makes a seawater refractometer but it's view is a bit darker and cut off. I found the veegee/vitalsine much easier to read. The Redsea seawater refractometer is the worse refractometer I've used due to it constantly loosing it's calibration. Milwaukee digital seawater refractometer is a good alternative for general checking. Otherwise there's some good conductivity probes out there. I've used the pinpoint salinity for many years as well.

Vee Gee Refractometer
http://www.thefilterguys.biz/refractometers.htm

For calibration I would suggest making your own via Randy's recipe.
Wrote up a thread on why I switched to making my own.
https://www.reef2reef.com/threads/does-your-calibration-solution-need-calibrated.250133/

 

[Val Shebeko]

Apex support has kindly offered to do a phone session to get this salinity probe thing to be put to bed.

Following the advice on a previous post I have ordered a True Sine refractometer which supposedly is the proverbial bee's knees for accurate measuring of salinity of seawater / tankwater.

Apex is advising the probe be calibrated to the salinity of the tank water and not the calibration solution to get a accurate reading of tank salinity.

In any case we shall see.

 

[jason2459]

Apex support has kindly offered to do a phone session to get this salinity probe thing to be put to bed.

Following the advice on a previous post I have ordered a True Sine refractometer which supposedly is the proverbial bee's knees for accurate measuring of salinity of seawater / tankwater.

Apex is advising the probe be calibrated to the salinity of the tank water and not the calibration solution to get a accurate reading of tank salinity.

In any case we shall see.

FWIW, conductivity is the preferred method these days. But Jim Welsh has a much more fun way to do it. https://www.reef2reef.com/threads/salinity-determination-by-density.238209/

 

[Val Shebeko]

Well, once I figure out how to use salinity and not kill my tank it too will be my preferred method.

But educate me here. Why is it the preferred method ?

 

[Randy Holmes-Farley]

Apex support has kindly offered to do a phone session to get this salinity probe thing to be put to bed.

Following the advice on a previous post I have ordered a True Sine refractometer which supposedly is the proverbial bee's knees for accurate measuring of salinity of seawater / tankwater.

Apex is advising the probe be calibrated to the salinity of the tank water and not the calibration solution to get a accurate reading of tank salinity.

In any case we shall see.

That's not needed

Well, once I figure out how to use salinity and not kill my tank it too will be my preferred method.

But educate me here. Why is it the preferred method ?

It is the method used by chemical oceanographers because it is instantaneous, continuous reading, temperature compensated, potentially more precise than the other methods available, and can easily be set up to read remotely, like at the end of a long line running down into the ocean.

Conductivity is actually how the salinity of ocean water is defined. PSU, practical salinity units, is the preferred unit of measure (similar to ppt). S=35 (no mention of units is needed for PSU with a capital S) is defined as seawater at 15 deg C with EXACTLY the same conductivity as a solution of 32.4356 g of potassium chloride in DI water to a total mass of 1 kg.

In chemical oceanography by Frank Millero, he gives the maximum precision of each of these methods using attainable devices (not hobby devices):
S = 35 +/- error below

+/- 0.05 refractive index
+/- 0.03 speed of sound
+/- 0.01 Composition analysis of major components
+/- 0.01 evaporation to dryness
+/- 0.004 density
+/- 0.002 chlorinity
+/- 0.001 conductivity

Note that any of these, if done perfectly, are WAY more accurate than needed by hobbyists

 

[Val Shebeko]

Do you have a link to this True Sine refractometer? If it's a vital sine refractometer it is a very good refractometer that's actually made by Veegee and should be closer to $100. DD H2Ocean also makes a seawater refractometer but it's view is a bit darker and cut off. I found the veegee/vitalsine much easier to read. The Redsea seawater refractometer is the worse refractometer I've used due to it constantly loosing it's calibration. Milwaukee digital seawater refractometer is a good alternative for general checking. Otherwise there's some good conductivity probes out there. I've used the pinpoint salinity for many years as well.

Vee Gee Refractometer
http://www.thefilterguys.biz/refractometers.htm

For calibration I would suggest making your own via Randy's recipe.
Wrote up a thread on why I switched to making my own.
https://www.reef2reef.com/threads/does-your-calibration-solution-need-calibrated.250133/

The gizmo shoul be here in a day or two and I will take a look. I paid near 200 for it plus freght, tax and calibration fluid. Plus I have nearly 1500 on the table with Apex and So far I am no closer to haveing areal understanding of how much salt is in the water. Very frustrating.

I appreciate the links and when the thing gets here I will send you details . Meanwhile I am off to peruse the do it yourself calibration fluid.

 

[Val Shebeko]

I think he Myka meant that, if you are measuring in ppt, you are usually shooting for a value around 34-35; whereas if you are measuring s.g., you are usually shooting for something like 1.025-1.026. 1.035 would be a crazy high value for s.g.

The Apex probe is showing 43.5 to 44. And my trusty 20 dollar refractometer is showing 1.025 .

When I look at a conversion table to take the salinity reading into Sg the values shown is way in the 1.03's.

The real issue here is who is right or even close to right and really how to establish that.

 

[Val Shebeko]

Thanks to everyone who responded.

. Entertainingly enough the probe and the 20 dollar wonder refractometer
Both read the same. Perfect !

 

[Randy Holmes-Farley]

The Apex probe is showing 43.5 to 44. And my trusty 20 dollar refractometer is showing 1.025 .

When I look at a conversion table to take the salinity reading into Sg the values shown is way in the 1.03's.

The real issue here is who is right or even close to right and really how to establish that.

DIY standards are the perfect way, if you have an accurate scale.

 

[jason2459]

Thanks to everyone who responded.

. Entertainingly enough the probe and the 20 dollar wonder refractometer
Both read the same. Perfect !

That's awesome I'm glad Neptune got you going. I like my Apex salinity probe a lot. I have two now with one in my display's weir and one in my sump. I also have a pinpoint salinity probe I keep in my new salt mixing container and use for other tasks. Then I'll spot check periodically with my veegee/vitalsine refractometer and my son uses my Milwaukee digital seawater refractometer for our 20 long mantis tank.

And do keep in mind the conductivity probe is susceptible to interference. Keep it away from bubbles as that can mess up the readings and some electrical equipment. Like I had an issue last year where my Apex probe would report wild results through out the day. I finally tracked it down to a T5 ballast that was causing the interference. I replaced the ballast and relocated the ballast farther from the probe and resolved that issue.

 

[Terence]

And do keep in mind the conductivity probe is susceptible to interference. Keep it away from bubbles as that can mess up the readings and some electrical equipment. Like I had an issue last year where my Apex probe would report wild results through out the day. I finally tracked it down to a T5 ballast that was causing the interference. I replaced the ballast and relocated the ballast farther from the probe and resolved that issue.

High voltage DC pumps are notorious for this. I absolutely LOVE my Abyzz pump, but it definitely interferes with the conductivity probe - luckily in a constant manner - so I have to do some workarounds to make things show the right values.

 

[Val Shebeko]

DIY standards are the perfect way, if you have an accurate scale.

?

 

[Randy Holmes-Farley]

?

Use a scale for anything but a rough check:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2004-06/rhf/index.htm

 

[Val Shebeko]

Got it.