Best tool to check salinity....

[Reef Puncher]

What do people use that they trust to check l salinity.

Used to use a refractometer albeit calibrated with rodi water on the zero line.

Bought a hanna salinity tester, calibratedcwith their fluid, granted I haven't been as calibrating as regular as I should but just tested the hanna and it was a smidge under 35ppt, calibrated it, tested the tank again and it was 33ppt, re calibrated it and the same result.

Used my old refractometer calibrated to zero with rodi 4x times and got 1.025.

So would you trust a refractometer calibrated to zero or this seemingly untrustworthy hanna item with proper calibration fluid, sensible answer suggests the hanna as im using the proper fluid but I've seen other people say these hanna things are not great.

Thoughts?

I used SEVERAL refractomters and hydrometers over the years. Then some people on a forum suggested this, and ive never used anything else since. it even comes with calibration liquid, and standard liquid to test it to make sure its 100% accurate. Its VERY reliable. only downside is the price. but its the best.

 

[Randy Holmes-Farley Verified Community Expert]

I used SEVERAL refractomters and hydrometers over the years. Then some people on a forum suggested this, and ive never used anything else since. it even comes with calibration liquid, and standard liquid to test it to make sure its 100% accurate. Its VERY reliable. only downside is the price. but its the best.

I agree it's a good device, but I'll note that the specification on accuracy is pretty wide. Perhaps it is just being honest compared to other refractometers, but they claim:

ACCURACY:±2 PSU | ±2 ppt | ±0.002 S.G. (20/20) | ±0.3°C / ±0.5°F

Thus, a reading of sg = 1.026 might be anything between 1.024 and 1.028.

 

[Reef Puncher]

I agree it's a good device, but I'll note that the specification on accuracy is pretty wide. Perhaps it is just being honest compared to other refractometers, but they claim:

ACCURACY:±2 PSU | ±2 ppt | ±0.002 S.G. (20/20) | ±0.3°C / ±0.5°F

Thus, a reading of sg = 1.026 might be anything between 1.024 and 1.028.

i wonder if they are just covering their backs with the statement. because i bought a liquid standard set at 1.026 and it comes with a standard at 1.025, and whenever i double check against these, it always matches on the dot. (hey while i have you i just posted a ph question on your forum)

 

[Pntbll687]

I use a Tropic Marin hydrometer.

Mix up some water and salt until it reads 1.025, then use this to calibrate my swing arm hydrometer.

I'll test with the Tropic Marin once a month or so to make sure the swing arm is still calibrated.

The biggest thing with the TM hydrometer is to make sure you rinse and dry it off after use.

 

[WillpoleReefers]

For me the optimum approach is use of both a TM hydrometer combined with a refractometer, the latter being calibrated to 35ppm seawater mixed/measured using the hydrometer for best accuracy. The refractometer is for quick checks including during mixing. The fragile hydrometer is used for a lot fewer measurements that way.