sailinity monitor solution????
 

so i bought a refractometer today and it came with "PINPOINT Salinity Monitor 53.0mS Calibration Fluid +-1% @ 77F/25C" Made by American Marine Inc.
I thought that i calibrate my refractometer by the PPT, and it would be calibrated(53 PPT)........ i tested my tank and it is really high, did i calibrate this right? do i calibrate it by the PPT or the SG(in ex. 1.030) and what is the # that i calibrate this particular solution to in PPT or SG????????

Try to get the calibration fluid exactly to 77F or as close as possible and then adjust your refractometer to read 35 PPT or about 1.0264.

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I don't think adjusting the temperature of the calibration fluid will be useful, since the fluid will quickly match the temperature of the refractometer. As indicated, the refractometer should be adjust to read 35 ppt or a SG of 1.0264

I have had and used an RHS 10ATC black handle for some years now. After reading all about needing the calibration fluid I did order it. Just tested my calibration. It was fine.

I have a question however. on my refractometer 35ppt is exactly equal to a SG of 1.025. What gives?

The refractometers we get have varying degrees of accuracy. Yours is within the normal range.

No, no, all go back and re- read Randy's article. That 35ppt on that refract is set to a solution of NaCl or table salt. Seawater IS NOT table salt and 35 ppt NaCl DOES NOT = 35ppt NSW. Actually, 35 ppt NaCl = 33.5 ppt Seawater. A refract is a function of light refraction and light does not refract the same way in NSW as it does in a solution of table salt. And the same for those SG conversion numbers on the refract. For Seawater, if you cal that refract in RO/DI water, then in Seawater it needs to read 36.5 ppt to = a 35 ppt Seawater value If and only if it is a real Lab grade refract, which those cheap Chinese ones are not

Refractometers and Salinity Measurement
[url]http://reefkeeping.com/issues/2006-12/rhf/index.php[/url]

[b]and it would be calibrated(53 PPT)b[/b]

No, not to read 53 ppt but 35 ptt. That 53.0 is mS not ppt and they are not the same, a different scale so to speak like inches vs centimeters.

Hold it guys. I don't think we're on the same page.

What I am saying is that on my refractometer a reading of 1.025 SG, not 1.0264, is aligned with a salinity of 35 ppt.

If I look at the conversion chart, a SG of 1.025 is indeed equal to 33.9ppt which closely agrees with what you're saying Boomer.

Here are my readings:

Using RO/DI water SG 1.0 Salinity 0

Pinpoint Calibration fluid SG 1.025 Salinity 35

My tank water SG 1.026 Salinity 36.5 (this is really hard to read because of the small scale)

I have read and reread Randy's article and I'm still stumped. Am I to assume that I have a salt refractometer and that the Salinity of 35 is that of a NaCl solution? If so, why does the pinpoint fluid reads as having a SG of 1.025 if it is comparable to sea water? It should be 1.0264.

My head is spinning by now.

Okay, I misunderstood you, I think. The scale on your refractometer is probably for a NaCl solution. That would explain why 35 ppt and SG 1.025 align, although reference temperature plays into SG as well.

In any case, I'd calibrate the refractometer to read zero with RO-DI water. Then I'd measure the PinPoint solution, and target that number for the tank.

Yes, I would agree with your first statement.

The refractometer adjusts for temperature so that shouldn't be a problem. I did wait the prescribed 30 seconds.

But then why does the PinPoint solution read 1.025 and 35, doesn't make sense to me, it should read 1.0264 and 36.5, not? This is what totally confuses me. May be the solution is not as precise as we think it is? If so, we're back at square one as far as adjusting our refractometers.

I know Randy had lengthy discussions with Lou about the solution being equivalent to sea water but is it really and consistently?

get a swing arm :)

The specific gravity of a solution changes with temperature, so SG is usually given normalized to a reference temperature, typically 25 C for our purposes. The refractometer might be calibrated for salt, and its reference temperature for SG is unknown, so how the two scales should line up is a bit blurry.

As to why the PinPoint measures 1.025, I go back to my first statement: these devices are of variable accuracy, and I wouldn't set much store in how they measure a solution when calibrated with RO-DI water.

[b]What I am saying is that on my refractometer a reading of 1.025 SG, not 1.0264, is aligned with a salinity of 35 ppt[/b]


[b]Hold it guys. I don't think we're on the same page[/b]


OK, now we are :D

It should not be. I have never heard of that. The scales are the same, 35 ppt vs 1.0264, for either NSW or NaCl. It is the spacing of the numbers on the scale that is different.

I only know 1 company makes a handheld refract for Seawater, supposedly and I have not contacted them yet but have my doubts. There are programmable electronic refracts that can be programmed to anything, like those from MISCO ~$600. I contacted a number of companies for Randy when he was doing his article. All were stunned when I told them their "seawater/salinity" refracts where wrong. I had to prove it to them. One company ATAGO, said they would remove it from their products list or get it fixed so it does measure Seawater. I do not know if they have done this yet but the refract is still on their website. The Salinity Refractometer S/Mill-E, ~ $200

The RHS 10ATC is made by Huake Instrument Co.,Ltd. This is the scale or should be. Maybe yours was built on a Friday :lol: And the scale is 1.0264 = 35 ppt NaCl. Does the 0 ppt line-up with the 1.00 and does 1.060 line-up with 80 ppt ?

[img]http://www.instrument-china.com/New_images/s10.gif[/img]

[QUOTE][i]<a
The RHS 10ATC is made by Huake Instrument Co.,Ltd. This is the scale or should be. Maybe yours was built on a Friday :lol: And the scale is 1.0264 = 35 ppt NaCl. Does the 0 ppt line-up with the 1.00 and does 1.060 line-up with 80 ppt ?

[img]http://www.instrument-china.com/New_images/s10.gif[/img] [/B][/QUOTE]


Boomer:

My scale looks the same as your picture but is further divided in 10th and of course the spacing is different:

The 0 ppt lines up with the 1.00
The 35 ppt lines up with 1.025
The 70 ppt lines up with 1.050 and,
to answer your question the 80ppt lines up with what looks like 1.058, a little hard to read without a line going across.

I just dug up my old Deep Six and my tank reads 1.026 or 35. It read 1.026 and 36.5 on my refractometer last night. It looks like I'll be fine if I continue to focus on keeping my SG as is and not worry about the salinity.

It's a good thing I never paid attention to the salinity side, mostly because it was easier to read the SG scale in 10th. Actually I didn't notice the discrepancy until I read that big long thread.

This was not a cheapo refractometer when I bought it 5-6 years ago. I wonder how many people are keeping their tank at a lower salinity than they think they are?

I ditched my Deep Six after reading threads saying how innacurate they can be. Well I did have a couple others that were not too accurate I must say. They hit the trash can.

Well then CJ out got an odd ball ;) There are 100's of hobbyists using the RHS ATC10. That pic came form their website. Either that or it is another chinese one and they are using the RHS 10ATC model # has it is so popular. But that makes no sense, as you have had yours for 5-6 years, and those we speak of have only been around for 3 years

May be some people will check their scales and get back to us. It is frustrating to say the least.

Thanks for the feedback Boomer.

You bet :D