Salinity Checking … What To Trust …

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Nhjmc

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Milwaukee here. Mehhh. Just got it about a week ago. Had some trouble getting it to calibrate ("LO" reading kept coming up when using as directed distilled water to calibrate as well as with RODI water) it took unhooking battery for a good ten seconds and putting hand over test well to block light to get it to work. Little disappointed as so many reviews and such stated "very easy to use" and could be I got a bunk unit (did email Milwaukee for help with what exactly the "lo" reading meant but never got a response).
 

salty joe

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I like my low budget refractometer a lot. But I got tired of not trusting calibration fluid so I got one of those big hydrometers and made a 'testing vase' out of 2" acrylic tube.

Every now and then, I'll check the refractometer against the hydrometer-sometimes it needs a tweak, sometimes not. But now, I trust my refractometer.
 
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DWill

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I use the Hanna tester and found it to be very accurate, although I did have a replacement as the temperature probe side of it was not reading correctly and therefore giving the wrong salinity.
I found if you closely watched the temperature reading you could see the digital display faultier and then get a false reading.
Maybe a batch of Hanna checkers faulty.??
It's possible. When I talked to Hanna about y checker the guy was pretty obviously aware of the problem. Both times.
This latest checker they sent me is accurate, however, it needs to be calibrated near constantly.

I should have the Tropic Marin hydrometer tomorrow, that will become my primary tool.
 

drblakjak55

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Really? Can’t trust the calibration fluids? How far are they off?
How bout thermometers? Not much better. Five different instruments, five different values. Does Randy know how to make an accurate thermometer?
 

salty joe

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After awhile, calibration fluid changes, even with the stopper in place. So, even if they are spot on to begin with, they have a shelf life.
 

ShepherdReefer

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What to trust…

I bought a Hanna salinity checker in March. The Hanna works well, it tracks my old school refractometer nearly perfectly; as long it’s it’s calibrated.

After the first few weeks of use it hold calibration well, usually a month or so. My experience is that in the first 2-3 weeks it has to be calibrated often, after a while it’s good to go. The other “issue” I’ve had is that the checker just doesn’t last long, I don’t know if it the carbon fiber probes, bad luck, or what the problem may be. I’ve replaced the checker under warranty twice in 6 months. The last time I had it replaced was a couple weeks ago.

During the weeks long sales last week I ordered a Milwaukee digital refractometer. It came in today.

I calibrated it and checked the water in my display. 1.031 was the reading.
That surprised me so I recalibrated, this time waitin a full minute to let the Distilled water temp equalize, I did the did the same the calibration check fluid. Checked the tank, again waitin a full minute … 1.029

I checked against my Apex salinity probe, which I never use for anything other than maybe a general trend monitor. The Apex reads 34.6 so “about” 1.026 (I keep my system at 1.026)

I break out the Hanna… 1.025.

I calibrate and use my refractometer … 1.026

I recalibrate and check with the Milwaukee … 1.030

I used the exact same procedure for everything; waithing one full minute before checking the result.

So…

Apex 34.5 (generally unreliable)
Hanna checker 1.025
Refractometer 1.026
Milwaukee 1.030 (1.029 was closest but still out of spec assuming any of the others is accurate)

I’m kinda disappointed actually. The Hanna seem accurate but it life span seems to short and I don’t know how many times Hanna will warranty their product before they just tell me no. Even though they know the issue exists because before I finished describing the problem the tech support guy was telling me how to attempt to “fix” it. It’s obviously a know issue.

The Milwaukee seems to be out of range. I seriously thinking about returning it now.

The old refractometer gives me what looks to be accurate results as long as I calibrate before each use.

So, what would you do?

What’s your experience with the Milwaukee?

I use multi-devices to make sure but as long you are within the acceptable limits, should be good. I use the Neptune Apex, refractometer, and Milwaukee. Milwaukee is the best so far.
 

S.Pepper

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I generally use my hanna to check my salinity and feel like it has been spot on for me, but i do check it against a cheap Instant Ocean hydrometer once a week. If there is a marked difference btwn the 2, I will get out my refractometer. I make sure i clean my hanna in r/o water after each use and I calibrate it at the first of each month.

I think It also helps that I have the same weekly water change schedule: 10% water change with the same amount of salt.
 

monicalooze

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Getting salinity measurements to agree is trickier than it should be.
The Milwaukee isn't necessarily the most accurate. Also note that Hanna makes an electronic refractometer which is exactly the same device as the Milwaukee, just a different color case.
You can make up your own standard, as mentioned. 35 g table salt in 1000 ml water is (approximately) 35 ppt.
You might try different calibration solutions. Some are designed only to be used with electronic conductivity meters and won't necessarily give an accurate number with a refractometer.
Another option is to get a precision hydrometer, like this one. This thing is huge, 13" in length, and graduated at 0.0001 SG increments. Seems quite accurate. Also can't go out of calibration. Too big to use in many sumps though.
I bought the hydrometer, but I'm disappointed because the scale on it does not allow you to calibrate to RODI water....it simply doesn't go low enough. You also have to adjust for temp, since it's calibrated to 77 degrees.

With salinity, I'm often left wondering "what is real?" I have a hydrometer, a refractometer, and the Hanna conductivity meter....they all read differently. I'm considering getting a hydrometer at a brewing store to make absolutely sure it's accurate, even if I have to do temp conversions
 
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infinite0180

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I use the Hanna, but i recently started making my own calibration solution using RHF article as a guide. I also baked my salt for 30min at 350 first. Come to find out the Hanna is great but the calibration packets are not...
 

Dr. Jim

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I bought the hydrometer, but I'm disappointed because the scale on it does not allow you to calibrate to RODI water....it simply doesn't go low enough. You also have to adjust for temp, since it's calibrated to 77 degrees.

With salinity, I'm often left wondering "what is real?" I have a hydrometer, a refractometer, and the Hanna conductivity meter....they all read differently. I'm considering getting a hydrometer at a brewing store to make absolutely sure it's accurate, even if I have to do temp conversions
I think many of us have the same problem, whether "we" realize it or not. I bought 3 different calibration solutions AND made Randy's DIY calibration solution (using a very accurate scale that measures to 0.01 gm). Those along with the T.M. High Precision Hydrometer helped me to settle on how to calibrate my refractometer.
 
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DWill

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So, the TM hydrometer came in. I’ve used it twice on two new batches of saltwater using TM Pro mix. To say the least confusion reigns.

I calibrated both the refractometer and the Hanna checker took two days to get the temp settled at near as possible to 77° using a Hanna Checktemp to check it. Temp was stable at 77.2. Mixed 2 10 gallon batches of water with a 1.026 target.

The first batch I checked with the Hanna and the refractometer first. Both the Hanna and the refractometer read exactly 1.026. Perfect right? Not so fast …

Dropped in the hydrometer… 1.0291 @ 77.2° F. what the heck?

Mixed up a second batch. This time I used the hydrometer to get to the target and “verified” with the Hanna and refractometer.

At 77.3° F the hydrometer read 1.0262. Perfect! But is it? Both the Hanna and the refractometer read 1.0231 now which is correct I have no idea.

I decided to check my tank water using the hydrometer. This is no easy task given the amount of water it takes to float the hydrometer and the depth of my lagoon tank (13”). But I was changing 10 gallons of water so I used a 10 gallon Brut can that I had mixed the water in ( I moved the clean water to two five gallon buckets).

Filled the Brut with tank water let it cool to near 77° (77.3° F) calibrated the Hanna and the refractometer just to be sure. Chalked the tank water 1.026 on the Hanna and maybe 1.0265ish on the refractometer but under 1.027.

Dropped in the hydrometer… 1.0294 … so which to believe. Especially remembering that my tank water measured 1.029 on the Milwaukee I returned.

I guess given the hobby grade equipment we use “close” is okay, so pick one.

I know my tank looks pretty good, I can’t believe I wouldn’t have some issues if the salinity was over 1.029 so I guess for now I’ll stick with a freshly calibrated Hanna backed up with a refractometer.
 

infinite0180

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So, the TM hydrometer came in. I’ve used it twice on two new batches of saltwater using TM Pro mix. To say the least confusion reigns.

I calibrated both the refractometer and the Hanna checker took two days to get the temp settled at near as possible to 77° using a Hanna Checktemp to check it. Temp was stable at 77.2. Mixed 2 10 gallon batches of water with a 1.026 target.

The first batch I checked with the Hanna and the refractometer first. Both the Hanna and the refractometer read exactly 1.026. Perfect right? Not so fast …

Dropped in the hydrometer… 1.0291 @ 77.2° F. what the heck?

Mixed up a second batch. This time I used the hydrometer to get to the target and “verified” with the Hanna and refractometer.

At 77.3° F the hydrometer read 1.0262. Perfect! But is it? Both the Hanna and the refractometer read 1.0231 now which is correct I have no idea.

I decided to check my tank water using the hydrometer. This is no easy task given the amount of water it takes to float the hydrometer and the depth of my lagoon tank (13”). But I was changing 10 gallons of water so I used a 10 gallon Brut can that I had mixed the water in ( I moved the clean water to two five gallon buckets).

Filled the Brut with tank water let it cool to near 77° (77.3° F) calibrated the Hanna and the refractometer just to be sure. Chalked the tank water 1.026 on the Hanna and maybe 1.0265ish on the refractometer but under 1.027.

Dropped in the hydrometer… 1.0294 … so which to believe. Especially remembering that my tank water measured 1.029 on the Milwaukee I returned.

I guess given the hobby grade equipment we use “close” is okay, so pick one.

I know my tank looks pretty good, I can’t believe I wouldn’t have some issues if the salinity was over 1.029 so I guess for now I’ll stick with a freshly calibrated Hanna backed up with a refractometer.
Buy a small digital scale on amazon. Bake some Mortons table salt at 350 for 30 min. in a clean container weigh 3.29g of Mortons salt and add enough rodi water to reach 100g. mix and use with the Hanna to calibrate. Next repeat the same process but use 3.65g of Mortons salt and use this for the refractometer. check tank water with both and see what they say...
 
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HuduVudu

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Too point:

 

HuduVudu

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So, the TM hydrometer came in. I’ve used it twice on two new batches of saltwater using TM Pro mix. To say the least confusion reigns.

I calibrated both the refractometer and the Hanna checker took two days to get the temp settled at near as possible to 77° using a Hanna Checktemp to check it. Temp was stable at 77.2. Mixed 2 10 gallon batches of water with a 1.026 target.

The first batch I checked with the Hanna and the refractometer first. Both the Hanna and the refractometer read exactly 1.026. Perfect right? Not so fast …

Dropped in the hydrometer… 1.0291 @ 77.2° F. what the heck?

Mixed up a second batch. This time I used the hydrometer to get to the target and “verified” with the Hanna and refractometer.

At 77.3° F the hydrometer read 1.0262. Perfect! But is it? Both the Hanna and the refractometer read 1.0231 now which is correct I have no idea.

I decided to check my tank water using the hydrometer. This is no easy task given the amount of water it takes to float the hydrometer and the depth of my lagoon tank (13”). But I was changing 10 gallons of water so I used a 10 gallon Brut can that I had mixed the water in ( I moved the clean water to two five gallon buckets).

Filled the Brut with tank water let it cool to near 77° (77.3° F) calibrated the Hanna and the refractometer just to be sure. Chalked the tank water 1.026 on the Hanna and maybe 1.0265ish on the refractometer but under 1.027.

Dropped in the hydrometer… 1.0294 … so which to believe. Especially remembering that my tank water measured 1.029 on the Milwaukee I returned.

I guess given the hobby grade equipment we use “close” is okay, so pick one.

I know my tank looks pretty good, I can’t believe I wouldn’t have some issues if the salinity was over 1.029 so I guess for now I’ll stick with a freshly calibrated Hanna backed up with a refractometer.

I think that you have a choice as to what to believe. You were having issues before with the other two, but now you have to choose which one you are going to believe.

You may want to send in an ICP test of your sample. This could be killing a fly with a shotgun, but it should give you some confidence as to which one is correct.

I feel your pain on this. :(

EDIT: Upon further thought maybe you could use the average of the two (three). This isn't ideal, but it seems like a good compromise.
 

Dr. Jim

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I recently received an ICP salinity reading from OCEAMO that was very high. When I questioned Dr. Denk about "how accurate is the salinity measurement that they use" he replied: "the salinity measurement is very accurate for your display tank (we are using a calibrated conductivity meter), the salinity of the other samples is only estimated from ICP data."

It turned out that his measured value matched the value my T.M. High Precision hydrometer gave me. (Of course, there is always the possibility that there could be some differences between different T.M. High Precision Hydrometers).
 

Saltyreef

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I think that you have a choice as to what to believe. You were having issues before with the other two, but now you have to choose which one you are going to believe.

You may want to send in an ICP test of your sample. This could be killing a fly with a shotgun, but it should give you some confidence as to which one is correct.

I feel your pain on this. :(

EDIT: Upon further thought maybe you could use the average of the two (three). This isn't ideal, but it seems like a good compromise.
With these kinds of measurements, you really have to only go based off one reading.
In this case, it should be the high precision hydrometer.
 
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