Salinity Questions

[jschrecongost]

Hi everyone,

My hanna salinity checker and instant ocean hydrometer give pretty significant differences. This is even after I calibrate the hanna checker. I am obviously inclined to trust the hanna over a hydrometer, but I just wanted to hear thoughts on this. The Hanna reads my tank at 33.5 ppt while the hydrometer reads at 38 ppt with no bubbles. I have had a fear that the hanna tester and calibration solution are just high in general, but I haven't heard anyone else with this issue. I just want to ensure I can trust the hanna checker. I have a refractometer, but my eyes really cannot focus on the refractometer long enough to get consistent readings.

Thanks,
Josh

 

[ZoWhat]

Swing arm hydrometers = Tonka Toy

You're putting the entire health of your tank and animals on a 2cent floating button tab glued on by a robot in China

 

[gbroadbridge]

Hi everyone,

My hanna salinity checker and instant ocean hydrometer give pretty significant differences. This is even after I calibrate the hanna checker. I am obviously inclined to trust the hanna over a hydrometer, but I just wanted to hear thoughts on this. The Hanna reads my tank at 33.5 ppt while the hydrometer reads at 38 ppt with no bubbles. I have had a fear that the hanna tester and calibration solution are just high in general, but I haven't heard anyone else with this issue. I just want to ensure I can trust the hanna checker. I have a refractometer, but my eyes really cannot focus on the refractometer long enough to get consistent readings.

Thanks,
Josh

If a recently calibrated Hanna Marine Salinity Tester says 33.5ppt it is 33.5ppt.

Throw away the Hydrometer.

You may also want to look up articles on how to create your own calibration solutions.
It is trivial, uses table salt, and saves money to be better spent elsewhere.

Regards
Graham.

 

[X-37B]

Get a TM floating hydrometer. Best unit as their is nothing to do but float it and read the SG.
I would not reef without one.

 

[Randy Holmes-Farley Verified Community Expert]

Get a TM floating hydrometer. Best unit as their is nothing to do but float it and read the SG.
I would not reef without one.

And somehow correct for temperature, and hope it was made correctly.

 

[Randy Holmes-Farley Verified Community Expert]

Hi everyone,

My hanna salinity checker and instant ocean hydrometer give pretty significant differences. This is even after I calibrate the hanna checker. I am obviously inclined to trust the hanna over a hydrometer, but I just wanted to hear thoughts on this. The Hanna reads my tank at 33.5 ppt while the hydrometer reads at 38 ppt with no bubbles. I have had a fear that the hanna tester and calibration solution are just high in general, but I haven't heard anyone else with this issue. I just want to ensure I can trust the hanna checker. I have a refractometer, but my eyes really cannot focus on the refractometer long enough to get consistent readings.

Thanks,
Josh

You can check both with DIY salinity standards if you have a scale and table salt, and even without one you can easily determine which is closer to accurate:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com

 

[X-37B]

And somehow correct for temperature, and hope it was made correctly.

You could say that for all hydrometers right?
I did check mine with the salinity standard though.
I have a swingarm, ouch.
I also have a refrac.

I think many get caught up in numbers in this hobby.

If your hydrometer of choice reads 1.026 and its really 1.025 or 1.027 does it really matter for the average reefer?
Keeping your numbers stable
within reason is more important, imo.
Well at least it has worked for me for over 30 years, lol.

Keep keeping us informed.

Thanks again for your time spent keeping us grounded in chemistry.

 

[Shirak]

I bought a NIST traceable floating hydrometer from Amazon for $28 Yes there is a slight temperature correction but it's not too difficult. The Tropic Marin version I think is corrected for 77 degrees already which is closer to most reef tanks than the one I got but I wanted a traceable one.
Most of the time I use my Hanna conductivity meter. I made the DIY calibration/reference solution for conductivity meters from Randy. Very simple to make and just do a quick check before using the meter.

 

[Randy Holmes-Farley Verified Community Expert]

You could say that for all hydrometers right?
I did check mine with the salinity standard though.
I have a swingarm, ouch.
I also have a refrac.

I think many get caught up in numbers in this hobby.

Swing arms temperature correct themselves, while floating devices do not.

My concern with temp is not so much the difference between the 77 deg F TM hydrometer calibration and 79 deg F in tank, but 77 calibration and 50 deg F new salt water, etc.

 

[X-37B]

Swing arms temperature correct themselves, while floating devices do not.

My concern with temp is not so much the difference between the 77 deg F TM hydrometer calibration and 79 deg F in tank, but 77 calibration and 50 deg F new salt water, etc.

That makes sense.
I add my salt to garage temp water. About 45° last week in my 275 ro/di tote.
I then bring it to temp and adjust SG up or down. After temp and SG are correct I adjust alk from 10+ to 8 and im good to go.

 

[jschrecongost]

Thank you for the responses everyone, I really appreciate them. Glad to hear that I should be confident in the calibrated Hanna checker, and I am planning to purchase a tropic Marin floating hydrometer just to double check it.

Best,
Josh