how often do you recalibrate your hanna checkers??

[Reeferbadness]

And after calibrating add 0.02 to the test result to get the real number. I'm on my second one and it's no better than the first. Compared to a calibrated refractometer and a TM hydrometer.

It’s not perfect but a heck of a lot more convenient than the Milwaukee or other checkers. I have 2 and have used them for 5 years without issue

 

[Dan_P]

Do we know this for certain? I know there is no adjustment accessible to the end user but has anyone opened one up to see if they have anything internal to them. Do they calibrate them at the factory, or are they just set devices?

Not that it matters all that much in the end as the required reference solutions are not readily available (as you noted) and it's something that would not be recommended to just about all hobbyists to perform, just curios.

@taricha took a Checker apart recently. I do not recall him finding anything to adjust.

 

[exnisstech]

It’s not perfect but a heck of a lot more convenient than the Milwaukee or other checkers. I have 2 and have used them for 5 years without issue

It is convenient but always being off bothers me. It's only adding 0.002 to the reading but what if it changes to 0.003 or. 0.004 and I don't know it. I just don't trust it for more than checking my tanks because they don't change lol

 

[RelaxingWithTheReef]

The salinity Checker is an entirely different type of device than the other Hanna checkers. It measures the electrical conductivity of the water, and needs to be calibrated. It’s a good method, but I don’t think the Hannah is the best device using it (by far).

What is your concern with the Hanna salinity checker?

The HI98319 has an accuracy spec of ±1.0 ppt for 0.0 - 40.0 ppt. I always clean the electrode surface and give it a good rinse before calibration. The reading is always within spec, around 1 ppt lower than multiple Oceamo ICP-MS results, and around 0.5 ppt lower than my TM hydrometer. My Hanna is stable, and appears to hold reasonable calibration for months.

The TM High Precision Hydrometer has an impressive resolution of 0.0001, but the maximum deviation is a disappointing 0.001 at 77° F (25° C). So a reading of 1.0260 could have a salinity of 33.188 to 35.827 (+- 1.32ppt).

With that said what method do you consider to be most accurate?

 

[Atalien2005]

This is what I use to make sure my Hanna Checkers are still returning valid results. I test against the recalibration solution about every 6 months and has been spot on every time.

 

[Randy Holmes-Farley Verified Community Expert]

Do we know this for certain? I know there is no adjustment accessible to the end user but has anyone opened one up to see if they have anything internal to them. Do they calibrate them at the factory, or are they just set devices?

Not that it matters all that much in the end as the required reference solutions are not readily available (as you noted) and it's something that would not be recommended to just about all hobbyists to perform, just curios.

What is your concern with the Hanna salinity checker?

The HI98319 has an accuracy spec of ±1.0 ppt for 0.0 - 40.0 ppt. I always clean the electrode surface and give it a good rinse before calibration. The reading is always within spec, around 1 ppt lower than multiple Oceamo ICP-MS results, and around 0.5 ppt lower than my TM hydrometer. My Hanna is stable, and appears to hold reasonable calibration for months.

The TM High Precision Hydrometer has an impressive resolution of 0.0001, but the maximum deviation is a disappointing 0.001 at 77° F (25° C). So a reading of 1.0260 could have a salinity of 33.188 to 35.827 (+- 1.32ppt).

With that said what method do you consider to be most accurate?

Many people report problems with the Hanna. It is a good method with an overly cheap implementation, IMO.

I believe that conductivity is the best all around method, and believe a number of issues confound various implementations.

I do not recommend leaving the probe in the water 24/7 as controllers do, and it do recommend higher quality devices than the inexpensive pen types.

I used an Orion model 128 for many years, using a 4 electrode probe on it. It never drifted.

 

[Randy Holmes-Farley Verified Community Expert]

This is what I use to make sure my Hanna Checkers are still returning valid results. I test against the recalibration solution about every 6 months and has been spot on every time.

I wonder if anyone has ever validated the values, especially over time.

 

[taricha]

@taricha took a Checker apart recently. I do not recall him finding anything to adjust.

yep, here's where I took apart a checker. nothing accessible to be changed.

If you knew a lot about the specific hardware (I don't) and had the appropriate devices and know-how to connect to the chip and reprogram it, you could probably change the stored regression equation that relates voltage decrease across on the photocell to absorbance to concentration. But the grand effect of that would literally just be the same as if you put an equation into a spreadsheet and mapped the displayed value on the checker to a confirmed value from measuring trusted stock. (this is how some of us have used checkers as just pocket-sized colorimeters.)

I wonder if anyone has ever validated the values, especially over time.

Rick and others found (some bottles) were missing 90% of the expected PO4.

Replication of PO4 test on my Fauna Marin Standard with HI-736 Phosphorous Checker
Fauna Marin Reported Levels
PO4---.2ppm (Actually .195ppm by weight)
NO3---10.0ppm (Actually 9.75 by weight)

Previous results:
First measurement---------1.0ppb P--- (.005ppm PO4)
Second measurement--- 4.0ppb P--- (.012ppm PO4)
Third Measurement-------3.0ppb P (.009ppm PO4)
Replication Today:---------6.0ppb P (.018 ppm PO4)


Nitrate Measurement ( My method using Red Sea Reagents and HI-764 Nitrite Checker)

10.7 ppm

maybe best to not put all your parameters in one solution.

 

[Randy Holmes-Farley Verified Community Expert]

yep, here's where I took apart a checker. nothing accessible to be changed.

If you knew a lot about the specific hardware (I don't) and had the appropriate devices and know-how to connect to the chip and reprogram it, you could probably change the stored regression equation that relates voltage decrease across on the photocell to absorbance to concentration. But the grand effect of that would literally just be the same as if you put an equation into a spreadsheet and mapped the displayed value on the checker to a confirmed value from measuring trusted stock. (this is how some of us have used checkers as just pocket-sized colorimeters.)




Rick and others found (some bottles) were missing 90% of the expected PO4.



maybe best to not put all your parameters in one solution.

Thanks!

 

[smitten with ocean life]

To calibrate the Checkers you will need to test them against a chemical reference standard not the color samples Hanna sells. You would need to make at least three different concentrations of the chemical reference and test each. These three results should form a straight line on a graph.The slope of the line is the calibration line. It will tell you how to adjust the future test results you obtain with aquarium samples. There is no physical adjustment to the Checker, just to the result.

Why do you think the Red Sea or Salfert results are any less suspect than the Hanna test results?

And if you feel like discussing it, what did you add and what test results are disturbing you?

i guess im just trying to go by what my tank looks like. just trying to figure out whats going on. i usually only use the hanna checkers. for example- was told my phos were way too high. so i wanted to get them down before something bad happened. ( it was .44) i starteded dosing red sea no pox. and some of my corals started going down hill. hanna now reads .27. but i started wondering about the hanna so got out my red sea test and it says .16. im not saying the red sea is more accurate or anything. just more wondering is something might have gone wacky with the hanna.... all i have to go by is what my corals are doing...

 

[Dan_P]

i guess im just trying to go by what my tank looks like. just trying to figure out whats going on. i usually only use the hanna checkers. for example- was told my phos were way too high. so i wanted to get them down before something bad happened. ( it was .44) i starteded dosing red sea no pox. and some of my corals started going down hill. hanna now reads .27. but i started wondering about the hanna so got out my red sea test and it says .16. im not saying the red sea is more accurate or anything. just more wondering is something might have gone wacky with the hanna.... all i have to go by is what my corals are doing...

An aquarium is soooo inscrutable. Nothing in our lives prepare us for raising such exotic creatures. I think this is part of the fun, frustration and fascination of the hobby, and why we can have endless and angry debates about the cause and effect of this and that.

I hope things work out so you that you can enjoy the aquarium.