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Varying salinity results

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So I’ve been using a classic handheld refractometer to monitor my salinity levels. I started off using boxed SW and it had a specific gravity of 1.024 so I’ve maintained that. (I’ve since switched to preparing my own SW)

 

I decided to buy a digital salinity tester because I’m finding it difficult to differentiate between levels on the refracto. I went with the Hanna digital salinity tester. I bought one, brought it home, calibrated it, and used it. It gave me a reading of 1.020. 

I was convinced this must be a mistake since my refractometer is reading 1.024-1.025 so I got the unit replaced today, and now it’s reading 1.021...

 

I guess my my refractometer is faulty? And the boxed sw at the LFS is only 1.020-1.021? Even though it’s advertized at 1.024-1.026? Or are the Hanna’s no good?

 

Everything is doing well in my tank. I never would have known the difference if I didn’t decide to go for the convenience of digital...

 

What should I do?

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4 minutes ago, Christopher Marks said:

What is the calibration process like? Maybe you can calibrate it again and double check? Boxed water should be at least 1.023 generally. 

It comes with a 35ppt calibration solution. 

I calibrated the first one 3 times and got the same results.

 

This new one I’ve only calibrated once but that should be all it takes.

 

the refractometer I’m comparing it to I’ve been calibrating with distilled water. 

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2 hours ago, CanadianReefKeeper said:

So I’ve been using a classic handheld refractometer to monitor my salinity levels. I started off using boxed SW and it had a specific gravity of 1.024 so I’ve maintained that. (I’ve since switched to preparing my own SW)

 

I decided to buy a digital salinity tester because I’m finding it difficult to differentiate between levels on the refracto. I went with the Hanna digital salinity tester. I bought one, brought it home, calibrated it, and used it. It gave me a reading of 1.020. 

I was convinced this must be a mistake since my refractometer is reading 1.024-1.025 so I got the unit replaced today, and now it’s reading 1.021...

 

I guess my my refractometer is faulty? And the boxed sw at the LFS is only 1.020-1.021? Even though it’s advertized at 1.024-1.026? Or are the Hanna’s no good?

 

Everything is doing well in my tank. I never would have known the difference if I didn’t decide to go for the convenience of digital...

 

What should I do?

I had my issues with the hanna hand held at first. It either does not calibrate well or their calibration solution is garbage. I am now reading consistant values with it but using their solution, I always get different readings. This past few weeks, 1.024 really means 1.026.   Previously,  it was 1.021,1.023. It is constant as in it doesnt deviate once set, but I still am double checking with the refractometer.  I mainly use it to compare my water change water with my tank water.  

1 hour ago, CanadianReefKeeper said:

It comes with a 35ppt calibration solution. 

I calibrated the first one 3 times and got the same results.

 

This new one I’ve only calibrated once but that should be all it takes.

 

the refractometer I’m comparing it to I’ve been calibrating with distilled water. 

I wouldnt however calibrate anything with distilled.  

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I would just get some calibration solution for the refractometer and I would trust that over hannah tbh. Lots of people check calibration before every use. I personally buy more expensive refractometers around $100 because they hold calibration a very long time but the cheap ones + checking often/re-calibrating as needed should work just as well. 

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I will recalibrate everytime i check and if i believe the result is "weird" ill check calibration again.

 

I just the red sea refractor and two fishs accurasea calibration fluid

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Did you calibrate your refractometer regularly with 35ppt calibration fluid?

 

Just an fyi, replace calibration fluid, it doesn't last forever.

 

I thought my refractometer was needing replacement because I was needing to calibrate it frequently - turned out to be the fluid. It's been spot on since buying new .

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2 hours ago, Clown79 said:

Did you calibrate your refractometer regularly with 35ppt calibration fluid?

 

Just an fyi, replace calibration fluid, it doesn't last forever.

 

I thought my refractometer was needing replacement because I was needing to calibrate it frequently - turned out to be the fluid. It's been spot on since buying new .

I’ve been using little single-use calibration packets that it came with. Never re-using them

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4 hours ago, CanadianReefKeeper said:

I’ve been using little single-use calibration packets that it came with. Never re-using them

Your refractometer came with calibration packets?

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1 minute ago, Clown79 said:

Your refractometer came with calibration packets?

Sorry no I’m confusing things...

The refractometer I’ve been calibrating with distilled water, as the instructions recommended. 

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22 minutes ago, CanadianReefKeeper said:

Sorry no I’m confusing things...

The refractometer I’ve been calibrating with distilled water, as the instructions recommended. 

 

 

You should be using calibrated solution not distilled water for the refractometer.  

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1 minute ago, Asureef said:

 

 

You should be using calibrated solution not distilled water for the refractometer.  

So everyone seems to be telling me...

I don’t understand why the instructions say to use distilled/rodi/demineralized water.

 

I guess I have some more shopping to do

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3 hours ago, CanadianReefKeeper said:

So everyone seems to be telling me...

I don’t understand why the instructions say to use distilled/rodi/demineralized water.

 

I guess I have some more shopping to do

It probably says that because it isn't accurate for the entire range it can read. If you are calibrating with distilled, your 1.00-1.005 will probably be spot on, but your 1.025 will be off. Calibrate near the range you want to keep.

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I think you should follow the directions in the manual for your specific device. I have a Milwaukee digital refractometer; you calibrate it using distilled water before each use. (It also comes with a standard 1.025 solution that you can use to check the accuracy of the meter, but it is not used for calibration.) In addition, temperature can affect the results, at least with the Milwaukee... directions say that if the temp of the sample differs significantly from the temp of the instrument you are supposed to wait approximately one minute before taking the reading. 

 

Also, I learned back when I was using a manual refractometer that required a calibration solution that I had to shake the solution to mix it before use. 

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17 hours ago, CanadianReefKeeper said:

Sorry no I’m confusing things...

The refractometer I’ve been calibrating with distilled water, as the instructions recommended. 

They all instruct that but they should be calibrated with 35ppt solution.

 

It's because most refractometer's are made for various uses, not just reef keeping, therefore when it's being used for a sw tank, you need to calibrate it with 35ppt solution.

 

My refractometer came with distilled solution, I can tell you when I checked with 35ppt solution, it was off because I calibrated with distilled for a year.

 

Your refractometer may not have an issue, just needs proper calibration.

 

Even old calibration fluid can and does cause inconsistency in readings. I thought my refractometer was going and it's an expensive one, it wasn't the refractometer but the solution.

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Which Hanna digital salinity tester do you have? Can you post a link?

 

Here are the calibration instructions for what appear to be their two main salinity devices. The handheld uses a 35 ppt calibration packet, whereas the tabletop one uses distilled water.

 

 

 

 

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42 minutes ago, Clown79 said:

They all instruct that but they should be calibrated with 35ppt solution.

 

It's because most refractometer's are made for various uses, not just reef keeping, therefore when it's being used for a sw tank, you need to calibrate it with 35ppt solution.

 

My refractometer came with distilled solution, I can tell you when I checked with 35ppt solution, it was off because I calibrated with distilled for a year.

 

Your refractometer may not have an issue, just needs proper calibration.

 

Even old calibration fluid can and does cause inconsistency in readings. I thought my refractometer was going and it's an expensive one, it wasn't the refractometer but the solution.

Huh okay very interesting. Thanks for the info!!

35 minutes ago, banasophia said:

Which Hanna digital salinity tester do you have? Can you post a link?

This is the tester I bought: https://www.reefsupplies.ca/online-store/Hanna-Marine-Salinity-Tester.html

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2 minutes ago, CanadianReefKeeper said:

Huh okay very interesting. Thanks for the info!!

This is the tester I bought: https://www.reefsupplies.ca/online-store/Hanna-Marine-Salinity-Tester.html

Ah, yeah... so that one uses their little 35 ppt packets that you submerge the device in... see videos I just posted above. If you decide you’re not happy with it, I would highly recommend a Milwaukee. 

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2 minutes ago, banasophia said:

Ah, yeah... so that one uses their little 35 ppt packets that you submerge the device in... see videos I just posted above. If you decide you’re not happy with it, I would highly recommend a Milwaukee. 

I was looking at the Milwaukee initially actually, but went with the Hanna for the price.

 

I’ll have to get some proper calibrating solution for my refracto and see what’s going on with everything and decide from there. 

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3 minutes ago, CanadianReefKeeper said:

I was looking at the Milwaukee initially actually, but went with the Hanna for the price.

 

I’ll have to get some proper calibrating solution for my refracto and see what’s going on with everything and decide from there. 

Yeah... I saw those Hanna handhelds were around $70 vs $110 for the Milwaukee, but if you have to buy those 35 ppt packets to use every time, as opposed to just using distilled, I was thinking it could add up... but since you already have it, may just need to make the best of it if you can get it to work properly. Good luck... look forward to updates. 🤗

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