Which salinity device to trust?

Sparky88

Well-Known Member
BRS Member
I agree with Acro. Ever since i invested in the Hanna Salinity & temp checker i have better control of the tanks i'm running. Now i'm slowly adjusting salinity due to the differences in the prior refractometers i was using before.
How do you insure that the reading you getting is accurate.
My water is 1 million $ per gallon...
Just kidding.
I give away my saltwater all the time.


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Ok bottle that some time and some exspierence and I'll take bottle of each
 

dz6t

Acro Garden, BRS Sponsor
BRS Member
I check my water using three device
Digital meter
Calibrated refractometer
Good old floating gravity meter.
Please not that all three measure different properties of salt water, their readings wont match each other exactly.
As long as the water is between 1.025 and 1.030, you are fine.


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Andy V

Well-Known Member
BRS Member
You can make your own calibration fluids, but of course that assumes you have accurate scales and can follow the directions properly (I bought calibrated weights to ensure my scale was correct). Randy Holmes-Farley has articles on how to do it. Make sure you understand what you are reading though, because there are a few different methods/fluids depending on what device you are using and/or what you are testing.

One thing I can say is that I used a Milwaukee Digital Meter for years. I always calibrated it the way you are instructed to. It was off by a lot. If I remember correctly, it was telling me 35ppt and was really like 31ppt. While I never had any trouble, I did go through years of corals growing very slowly. This may have been a factor.

I now use a $500+ Orion lab grade probe, which is probably overkill, but I got it used for $150, which is close in price to the Pinpoint, while being far superior.
 

Cpage101

Corey- 2019 BRS BOD
BRS Member
Officer
you can go by taste too I can tell the difference between 1.026 and 1.030[emoji2957][emoji2957][emoji23][emoji23]


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mchartier

Well-Known Member
BRS Member
Anyone around the Providence/Southcoast area have a calibrated digital meter? I made calibration solution and I would like to test it against something else. I have 2 liters of it so I can spare some for letting me test it.
 

reefer125g

Well-Known Member
BRS Member
I have to go with the Hanna . Just went through the same thing . Add a kh checker to that list also.
 

Greg Hiller

BRS Moderator
Staff member
Moderator
BRS Member
I'd just make your own standard, specifically for a refractometer (as mentioned earlier in this thread Randy H-F has an article about how to do it (http://reefkeeping.com/issues/2004-06/rhf/index.php). Half decent balances are not that expensive, particularly for larger weights, and table salt is super cheap, as is a gallon of distilled water from the drug store (or if you have an RO/DI system). You can make up a 3.65 weight percent sodium chloride (use standard table salt, not any fancy stuff) solution using 79.3 grams of table salt and 2104 grams of water. If you get a decent scale that works in the 79 gram range you could then just weight the water in small aliquots (portions) and keep adding it to your container.


 

serwobow

Well-Known Member
BRS Member
I'd just make your own standard, specifically for a refractometer (as mentioned earlier in this thread Randy H-F has an article about how to do it (http://reefkeeping.com/issues/2004-06/rhf/index.php). Half decent balances are not that expensive, particularly for larger weights, and table salt is super cheap, as is a gallon of distilled water from the drug store (or if you have an RO/DI system). You can make up a 3.65 weight percent sodium chloride (use standard table salt, not any fancy stuff) solution using 79.3 grams of table salt and 2104 grams of water. If you get a decent scale that works in the 79 gram range you could then just weight the water in small aliquots (portions) and keep adding it to your container.
OK, so I took your advice, and made a 35ppt sodium chloride solution. I weighed out 17.5g NaCl and dissolved that in 482.5g DI water. I checked the refractive index of this solution against the BRS standard that I had, and they were both identical as far as I could tell. So, now I have a bunch more calibration solution, and I am confident that it (and the BRS standard), and most importantly my tank water are all in the correct range. Thanks!
 

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