Hanna Alkalinity Cuvette Off?

[Hair Algae Wizard]

Folks,

Is it just me, or is the 10ml line on the cuvette actually not 10ml? I have an electronic pipette, and noticed that drawing 10ml out with it, actually is higher than the line marked on the cuvette. I also benchmarked this against other 10ml pipette's, and the Hanna supplied cuvette is definitely off.

Is it just me? Lol, maybe I'm doing something wrong?

 

[reefiniteasy]

Mine are like that. I just use a syringe to fill 10ml.

 

[Reefer5640]

All of mine are the same and I have 10. Are you measuring to the bottom of the meniscus or the top of the concave?

 

[homer1475]

Lines have always been off on any Hanna cuvette I have owned as well as several batches of replacements.

The bottom of the meniscus is definetly above the 10ML line on the cuvette.

 

[Reefer5640]

So it sounds like you all fill to a true 10 mls rather than using the line as the fill level. I’ve done it both ways but I’ve always wondered if the people at Hanna are considering this 10 mls and therefore the test is more accurate using their line. Or is it just a manufacture error and it’d be more accurate to use a true 10 mls? I assume a true 10 mls is the way to go and it’s what I do as well. Honestly as long you stick to the same method and maintain stability I’m sure the margin of error is minimal but still irritating that the line is off.

 

[homer1475]

I always use a syringe just because after a while the hanna line wears off. So even on new ones(just because its habit) I use a syringe to fill them.

But I would agree that as long as you do it the same way everytime, a couple drops won't make a huge difference.

 

[reefiniteasy]

So it sounds like you all fill to a true 10 mls rather than using the line as the fill level. I’ve done it both ways but I’ve always wondered if the people at Hanna are considering this 10 mls and therefore the test is more accurate using their line. Or is it just a manufacture error and it’d be more accurate to use a true 10 mls? I assume a true 10 mls is the way to go and it’s what I do as well. Honestly as long you stick to the same method and maintain stability I’m sure the margin of error is minimal but still irritating that the line is off.

I have cuvettes where the line is different on each.

 

[Hair Algae Wizard]

I've noticed that on my Alkalinity Checker, my readings are off by .5 - .8 compared to what my Trident shows, when using the line Hanna provides. When I fill the cuvette with an electronic pipette, the difference is within .1 - .2

 

[Thaxxx]

Kind of makes you think if they can't even get a simple line correct for a supposedly precise test. How accurate is the reagent and tester?

 

[Soryu]

Folks,

Is it just me, or is the 10ml line on the cuvette actually not 10ml? I have an electronic pipette, and noticed that drawing 10ml out with it, actually is higher than the line marked on the cuvette. I also benchmarked this against other 10ml pipette's, and the Hanna supplied cuvette is definitely off.

Is it just me? Lol, maybe I'm doing something wrong?

I used to work in medical devices and one of the things we produced were syringes. We had to monitor the pad printing machine hourly and any time we found they weren't accurate all of our product produced between that hour was disposed of. But even then the accuracy of the syringe was never going to be 100% perfect. But I can tell you for certain that our 1ML and 10ML syringes were far more accurate than the pad printing on the Hanna cuvettes. I can guarantee you they're not anywhere near the testing standards we used and I trust my syringes over the line on the glass cuvette. Having said that all of my Hanna cuvettes are pretty close to syringes but the meniscus line is always slightly above the line on the Hanna cuvette and each one is slightly different. I would personally trust the pipette.

 

[Spieg]

This seems to come up about once a week on this site. All my vials seem to be pretty identical and fill to the line with 10 grams of water. Guess I'm just lucky. ;)

 

[X-37B]

This seems to come up about once a week on this site. All my vials seem to be pretty identical and fill to the line with 10 grams of water. Guess I'm just lucky. ;)

At least once a week, lol.
I posted this on another thread.
I filled mine to the line and got 7.1 alk. Added another .1ml and the result was 7.3.
Thats within the .3 error of the unit.
Salifert is close enough too and I use it to spot verify the Hanna once a month.
As long as you always fill to the same spot the results are repeatable.
I would bet most peoples alk varies by .3 or more anyway.
Pretty sure Hanna does not make or put the line on the vials either.

 

[Urtoo]

The meniscus to the line is 9.9 on all 10 of my curettes. I use the same 9.9 every time, so I assume with the reliability of a hobby kit like this, as long as you are consistent, you are good.
Also, my readings are similar to ICP testing too, so I got that to fall back on when in doubt. Only off by .1 on the worst test metric I can see

 

[ingchr1]

There was another thread on this recently.

https://www.reef2reef.com/threads/hanna-cuvettes-are-off.767746/

 

[Ippyroy]

They are all of. I got a single channel pipette and all is good. I use it for all of my testing. It makes life so much easier. It is the greatest thing I have purchased for my reef.
Amazon product ASIN B01IP5Q5CS