Salinity Testing Issue - Please Help!

[Miami Reef]

Guys, should I go ahead and order the TM glass hydrometer? I wouldn’t get here for a few days to a week, but going forward I think this would be best as it needs no special storage or calibration. Would you guys agree?

I highly recommend it. That’s what I use for my reef tank.

The Milwaukee is only used to general check ups, QT, or in water storage tanks.

Pick up a 500 mL plastic graduated cylinder from Amazon. The hydrometer needs to float in a deep body of water.

 

[Miami Reef]

Hydrometers don’t have ATC, so here’s a quick calculator:

https://www.hamzasreef.com/Contents/Calculators/SalinityCorrection.php
You’ll need a thermometer. The TM hydrometer is calibrated at 77F, so leave that in the “unit calibration” field. Just input the measured salinity and temp of the water at the time measured.

 

[Fish Fan]

Despite the claimed accuracy of Milwaukee (+/- 2 ppt), I find it spot on.

Dissolve 3.65 grams of sodium chloride (Morton Iodized) in 96.35 grams (mL) of purified freshwater to make a 35 ppt or 1.0264 sg refractometer standard.


https://reefkeeping.com/issues/2004-06/rhf/index.php

I lied above, my kitchen scale only reads grams in whole numbers :-(

I highly recommend it. That’s what I use for my reef tank.

The Milwaukee is only used to general check ups, QT, or in water storage tanks.

Pick up a 500 mL plastic graduated cylinder from Amazon. The hydrometer needs to float in a deep body of water.

Yes, I'm going to order both right now. I should have had one all along.

Hydrometers don’t have ATC, so here’s a quick calculator:

https://www.hamzasreef.com/Contents/Calculators/SalinityCorrection.php
You’ll need a thermometer. The TM hydrometer is calibrated at 77F, so leave that in the “unit calibration” field. Just input the measured salinity and temp of the water at the time measured.

Perfect, thank you!

 

[Miami Reef]

Here’s the graduated cylinder: https://a.co/d/hPc4XFl

I think you’ll love the TM Hydrometer.

 

[KStatefan]

I lied above, my kitchen scale only reads grams in whole numbers :-(


Yes, I'm going to order both right now. I should have had one all along.


Perfect, thank you!

Just make a bigger batch then ie 36 grams in 963 ml

 

[Fish Fan]

When your glass hydrometer comes, check you Milwaukee for "consistency." Even if it is not spot-on "accurate", at least if it is "consistent" you will know what mental adjustment (+|-) to make, right? (I love the convenience of my Milwaukee; plus mostly I run FOWLR tanks, so the salinity level is much less of a big deal.)

Thank you. I get that as long as it's consistant it would still be useful. I'm going to order the glass hydrometer now and then I'll know for sure.

I also may just order some 35 ppt standard as I'm having a hard time finding a way to precisely measure the salt and water at home.

 

[Fish Fan]

Here’s the graduated cylinder: https://a.co/d/hPc4XFl

I think you’ll love the TM Hydrometer.

Thank you, I was actually going to spring for a glass cylinder, but I'll check this one out.

 

[BeanAnimal]

Hydrometers don’t have ATC, so here’s a quick calculator:

https://www.hamzasreef.com/Contents/Calculators/SalinityCorrection.php
You’ll need a thermometer. The TM hydrometer is calibrated at 77F, so leave that in the “unit calibration” field. Just input the measured salinity and temp of the water at the time measured.

or here :)

https://beananimal.com/tools/tropic-marin-precision-hydrometer-correction-calculator/

 

[Fish Fan]

Just make a bigger batch then ie 36 grams in 963 ml

Yeah, I may have to at this point. Could I store this fluid is something like a plastic 16 ounce water bottle? HOw long would it keep for?

 

[Randy Holmes-Farley Verified Community Expert]

Yeah, I may have to at this point. Could I store this fluid is something like a plastic 16 ounce water bottle? HOw long would it keep for?

Forever, if it does not evaporate.

 

[Fish Fan]

Forever, if it does not evaporate.

Thank you much! So cap on bottle and I should be good for a while :)

 

[KStatefan]

Yeah, I may have to at this point. Could I store this fluid is something like a plastic 16 ounce water bottle? HOw long would it keep for?

as long as it is sealed air tight for a long time, but it is also less than 25 cents worth of salt

 

[KStatefan]

Thank you. I get that as long as it's consistant it would still be useful. I'm going to order the glass hydrometer now and then I'll know for sure.

I also may just order some 35 ppt standard as I'm having a hard time finding a way to precisely measure the salt and water at home.

I use a glass cylinder it is easier for me to see thru.

I would invest in a scale before i purchased anybodies standard.

 

[BeanAnimal]

FWIW I use a 1000ml glass graduated cylinder. I fill it to the top so that I can see the reading and meniscus... but i take a photo, as even with reading glasses, I can't read it well.

@A_Blind_Reefer -- I know you trust your MW digita - but the hydrometer would be a good sanity check and standard as well. You can alway take a photo or have a family member read it, when you do use it.

 

[BeanAnimal]

I would invest in a scale before i purchased anybodies standard.

A good 0.001 g scale isn’t that expensive. Used lab balances can be picked up pretty cheap. I use mine all the time for reef stuff, bread making (yeast, salt, etc.), even weighing granular ant killer (don’t ask). Also great for sanity-checking dosing pump calibrated by volume.

I also keep various glass ASTM Class A graduated cylinders, small volumetric flasks and pipettes for things like making standards, diluting reagents, filling testing vials, etc.

 

[Fish Fan]

as long as it is sealed air tight for a long time, but it is also less than 25 cents worth of salt

I get it, it just seemed like a lot of the solution, and if I can store it and know that I can trust it, I'll use it more often.

Knowing I can store it is big with me, I am fearful of things like pH or TDS pens, and even my Hanna salinity checker as I always question if they were stored correctly, and are accurate long term. I'm probably over thinking all of this :confused:

 

[Fish Fan]

A good 0.001 g scale isn’t that expensive. Used lab balances can be picked up pretty cheap. I use mine all the time for reef stuff, bread making (yeast, salt, etc.), even weighing granular ant killer (don’t ask). Also great for sanity-checking dosing pump calibrated by volume.

I also keep various glass ASTM Class A graduated cylinders, small volumetric flasks and pipettes for things like making standards, diluting reagents, filling testing vials, etc.

Thank you for your help here!

I will look for a scale. I don't like to be unsure, and this seems like the right way to go, along with the hydrometer I'm going to order.

Thanks again!

 

[IceNein]

Thank you, I was actually going to spring for a glass cylinder, but I'll check this one out.

In my opinion there is no need for a glass cylinder since the only thing you want the cylinder for is to hold water. People just recommend 500ml graduated cylinders since they're the right size and shape for the hydrometer.

 

[Fish Fan]

In my opinion there is no need for a glass cylinder since the only thing you want the cylinder for is to hold water. People just recommend 500ml graduated cylinders since they're the right size and shape for the hydrometer.

Thank you, I do see your point, but my plan was to use the graduated cylinder for measuring water as well, like in making Randy's DIY calibration fluid. Additionally, I believe glass will be a little easier if I have to see through it to look at the hydrometer. But thank you for the suggestion.

 

[Fish Fan]

Alright, I did my best to make Randy's DIY 35 ppt standard by measuring on my humble kitchen scale 963 mL of RODI water and 36 grams of a basic table salt without iodine. I stirred with a whisk, and then zapped it for a few seconds in the micro to bring up the temp a little. Here's what I got.

With the standard solution at 73.3 F on my Hanna Checktemp 1 and at 73.1 F on my Hanna salinity tester:
The Hanna salinity tester reported 38.7 ppt
The Milwaukee refractometer reported 35 ppt

I think that's pretty compelling right there. What do you guys make of these results?