Hanna salinity checker vs refractometer

[mike550]

@Piece of reef your Hanna is accurate to within 0.001 so let’s say the actual reading is 1.026. Then if your refractometer is “perfect” you’re only off by 0.001

I’d trust the Hanna as long as you keep it calibrated as it’s less prone to human error. Personally, I wouldnt worry about the difference you’re seeing. Close enough for this hobby

 

[gbroadbridge]

A hydrometer/floater cannot be calibrated since it measure salinity by the density of the water, and therefore more reliable than devices that needs to be calibrated. But as saltwater density depend on the temperature the result have to be calculated to give the actual salinity.
Calculator suggestions:

Salinitetsberegner

Omregning af enheder vedr. salinitet i saltvandsakvarie. Understøtter ledningsevne (mS/cm), salinitet (PSU og ppt), densitet (g/cm³) og relativ densitet.

reefapp.net

Aquarium Calculators

An index of useful aquarium calculators and converters.

www.hamzasreef.com

A hydrometer is calibrated when manufactured.

The can lose their calibration if they are not protected against damage, in the same way that any instrument can lose calibration.

 

[MBruun]

A hydrometer is calibrated when manufactured.

The can lose their calibration if they are not protected against damage, in the same way that any instrument can lose calibration.

Yes they are calibrated/tested when manifactured, but it is not an option for the user to calibrate it. If the hydrometer are damaged it is not the same as a refractometer loose the calibration IMO

 

[flashsmith]

Get a TM hydrometer and never look back. No fluid and no packets. No guessing.

 

[shadyraro]

My Hanna does exactly the same, it reads 1.025 while my refractometer reads 1.027 and both were calibrated before use. My Hanna is now an expensive temperature gauge.!

 

[Piece of reef]

My Hanna does exactly the same, it reads 1.025 while my refractometer reads 1.027 and both were calibrated before use. My Hanna is now an expensive temperature gauge.!

I ended up buying a milwaukee salinity tester, it was expensive but my hanna was wrong unfortunately

 

[shadyraro]

I ended up buying a milwaukee salinity tester, it was expensive but my hanna was wrong unfortunately

I use a few Hanna checkers, alk, nitrate hr and phosphate ulr and they’re all pretty accurate. But yeah the salinity tester I just don’t trust anymore. I’ll be getting a reef factory salinity guardian soon as I’ve read good reviews about it, plus I have a couple of other RF devices so it makes sense.

 

[Reef.]

@Piece of reef your Hanna is accurate to within 0.001 so let’s say the actual reading is 1.026. Then if your refractometer is “perfect” you’re only off by 0.001

I’d trust the Hanna as long as you keep it calibrated as it’s less prone to human error. Personally, I wouldnt worry about the difference you’re seeing. Close enough for this hobby

0.001 is quite a lot, the Tropic Marin measures to 4 decibels places.

 

[Reef.]

How did you check the calibration of the hydrometer?

Make 500mls of Randy DIY calibration fluid and test it, I tested mine, think it was around .0001 off.

 

[gbroadbridge]

Make 500mls of Randy DIY calibration fluid and test it, I tested mine, think it was around .0001 off.

Randy's DIY calibration solution method is not accurate to 0.0001 as described.

 

[mike550]

0.001 is quite a lot, the Tropic Marin measures to 4 decibels places.

I really have to disagree with you on this one. A 0.001 discrepancy over lets say 1.025 is around a 0.1% error. When you consider significant figures you’re good.

You‘re confusing resolution with accuracy. The TM spec for the hygrometer is

• Maximum deviation: 0.001 at 77° F (25° C)
• Scale from 1.021 to 1.031
• Resolution: 0.0001

So while you could resolve to 0.0001, you’re only accurate to within 0.001 at 25C. So same as the Hanna

 

[mike550]

Make 500mls of Randy DIY calibration fluid and test it, I tested mine, think it was around .0001 off.

How do you know your homemade calibration fluid was within spec to read 0.0001 accurately.

 

[Reef.]

Randy's DIY calibration solution method is not accurate to 0.0001 as described.

And my scales aren’t that accurate either, or my thermometer, I said my hydrometer read 0.0001off what the calibration fluid was meant to read. That is really as much as I can hope for. There are a lot of variables, my thermometer is certified to 0.1c -/+ that is still enough to make any claim that the hydrometer is accurate to 0.0001 meaningless to some extent.

All things being equal I believe the hydrometer is a lot more accurate than the stated 0.001 Hanna.

 

[Reef.]

How do you know your homemade calibration fluid was within spec to read 0.0001 accurately.

I don’t, same as I don’t know that a packet of Hanna calibration fluid is as stated either, I believe the Hanna also temp corrects, I bet the Hanna temp probe has a margin of error or around 1 degree, we have to at some point take these things at face value or we would go mad.