Tropic Marin Hydrometer

[Alamo183672]

Am I correct that using the Tropic Marin hygrometer at 77-78f is the most accurate way to check salinity?

 

[Ef4life]

Accurate- it should be, most consistent - absolutely

 

[exnisstech]

I don't know that it's the most accurate but i find mine accurate enough that I trust it's reading at 77 degrees and use that salt water to calibrate my refractometers. I've read that a good conductivity meter is most accurate but I have no first hand experience with a high end meter. I recently bought a pinpoint meter and find it accurate enough for my use. I typically use the hydrometer at my mixing station and use the pinpoint for checking tanks because it's easier to use especially checking multiple tanks.

 

[EricR]

I trust the TM hydrometer enough and as others have said -- it's consistent.
*broke one so now keep a spare and the 2 I have match VERY CLOSELY when direct compared

I run my tank at 77d F anyway so use the TM hydrometer in 500mL standing (plastic) cylinder for checking tank salinity.

For water change water, I just use Hanna digital to match new water to DT because it's quick/easy and has ATC <-- I don't normally heat my new water change water.

 

[exnisstech]

For water change water, I just use Hanna digital to match new water to DT because it's quick/easy and has ATC <-- I don't normally heat my new water change water.

How do find the Hanna accuracy compared to the hydrometer? I've had two of them and calibrated using Hanna calibration fluid they both always read 0.002 low. Not a big deaI as i could allow for the difference but I could calibrate them to 1.025 using saltwater confirmed to be 1.025 and they would read accurately but I just didn't trust them so i bought the pinpoint.

 

[EricR]

How do find the Hanna accuracy compared to the hydrometer? I've had two of them and calibrated using Hanna calibration fluid they both always read 0.002 low. Not a big deaI as i could allow for the difference but I could calibrate them to 1.025 using saltwater confirmed to be 1.025 and they would read accurately but I just didn't trust them so i bought the pinpoint.

I never had good luck with the Hanna calibration fluid,,, not sure why.
I had much better results using Randy's DIY salinity calibration standard for EC meters,,, and I'd just float in a container in my tank to get to normal temp (77d).

Mine actually held calibration well but I've heard others complain about that so maybe I got lucky.

Now-a-days, I rarely calibrate it and just use it as a way to "match" my new water to my tank salinity, as I mentioned.
*if I decide to calibrate, I normally just calibrate to my tank salinity, which I run right about 35 ppt anyway

 

[RobertK]

I doubt its the most accurate but for most hobbyists it is accurate enough.

I performed a one-time check of my TM hydrometer using Randy's specific gravity standard to make sure it was accurate from the factory. I use BeanAnimal's correction calculator to correct SG readings taken at temps other than 77°F. I calibrate my refractometer using the readings I get with the hydrometer, as I find it simpler to use for quick checking.

 

[Randy Holmes-Farley]

Am I correct that using the Tropic Marin hygrometer at 77-78f is the most accurate way to check salinity?

No, absolutely not, but that is likely not really what you want to know.

It is accurate enough for reefing, and it cannot be miscalibrated by hobbyists, but to claim it is the most accurate is far from the truth.

It may be the most accurate device reefers use that costs less than $50, but there is a reason that scientists and oceanographers use conductivity and a reason the modern salinity scale is defined in terms of conductivity.

 

[Randy Holmes-Farley]

FWIW, I edited the title to hydrometer. Hygrometers measure humidity. :)

 

[WhatCouldGoWrong71]

It’s the only thing I use.