PDA

View Full Version : Hanna checker for Nitrate update


Scubajoe1
09/29/2015, 07:20 PM
So I spoke to the folks at Hanna today and asked...


Hi there, I am a chemist and an avid marine aquarium enthusiast. I was curious as to why Hanna has not come out with a nitrate marine test kit. I have made a standard curve in my lab for nitrates at 0,1,2,3,4,5 and 10 ppm. From this curve I am able to elucidate the nitrate concentration for my reef aquarium by running the sample through a UV spectrometer and getting an absorbance reading. It seems the chemistry is already established for the reaction and there is a HUGE market value for a digital test kit for nitrate. I use the Hanna checkers for all my other assays and was wondering why the nitrate test kit has not been introduced. Can you please forward this to your R&D department for a possible explanation and suggestion.

They quickly replied with...

Thank you for your input regarding a Nitrate Checker HC. It would not be a stretch for us to offer a Checker HC for Nitrate testing since we currently offer the HI96728 portable version. All of the Hanna Checkers are based on previous versions of our portable colorimeter line. The current portables use a tungsten lamp with a narrow band interference filter that excluded all other wavelengths except the one of interest. The previous versions used an LED at a specific wavelength as a light source. The majority of the Checker HC’s are using an LED as a light source.

The portable meter for nitrate is using 525 nm which we have an LED for, so from a mechanical standpoint there are no issues. From a chemistry standpoint the cadmium reduction method has two issues:
There is a chloride interference above 100 mg/L. This would seem to be overcome if the curve is developed with standards prepared in artificial seawater.
The method is very sensitive to how the sample is mixed. This is a bit of challenge. In order to get consistent results an SOP would have to be developed in which the mixing procedure can be standardized and repeatable. It might have to include the use of a magnetic stirrer.
The above are what I believe to be the reasons that we have not moved forward with a Nitrate Checker. I will have to confirm with the R&D Department.

Out of curiosity, are you using a chemical method when doing the absorbance measurement in the UV range? I know that in process measurements of nitrate at a wastewater plant a UV based sensor (210 nm) is used in situ. There is no chemistry so I want to make sure that this is the technology that you are referring to. If it is not and you are using a chemical method then any information about the method would be useful.

Lastly, As we have the alkalinity Checker for saltwater aquariums, I am curious if we should offer a unit that displays in dKH as opposed to calcium carbonate. It seems that in the forums dKH is more common. Since it is only a change in programming it would be relatively easy to do as well.

If I find out more information then I will forward on to you as well.

Sincerely,

Paul Fabsits
VP of Product Marketing
Hanna Instruments


Hello Paul,
Thanks for getting back to me so quickly. I think the hanna alkalinity checker is fine….similar to the phosphorus one we just have to multiply or divide by a constant. Ideally the phosphorus checker should measure phosphate instead of phosphorus because that’s what we are interested in but like I said not a deal breaker.

In regards to the nitrate test I currently use the chemistry in the red sea test kit and do make the standards in salt water. I then tested a standard I made against the standard curve and come out pretty close. I did not need a stir bar….I mix 5 drops and shake for 15 seconds, add one scup of reagent two and shake for a minute and then one scoop of reagent three and shake for 15 seconds. Then you wait 9 minutes and read. I did find that I had to filter the sample through a 0.22 or 0.4 micron filter to obtain the best reprducible results.

I would also maybe make a high range and a more accurate low range meter as well.


Hope this information helps.


Joe

So we will see what comes next

IvanTheTerrible
09/29/2015, 08:38 PM
A digital nitrate kit would be great. :celeb3:

I'm colorblind, so I "recruit" my kids to help. Life would be much easier with a digital checker.

Scubajoe1
09/29/2015, 08:52 PM
Good feedback. I will pass that along as well.

laga77
09/30/2015, 08:12 AM
Lastly, As we have the alkalinity Checker for saltwater aquariums, I am curious if we should offer a unit that displays in dKH as opposed to calcium carbonate. It seems that in the forums dKH is more common. Since it is only a change in programming it would be relatively easy to do as well.


I think a lot of people who are not chemists, like me, would prefer the display in dKH.

Scubajoe1
09/30/2015, 08:16 AM
Will let them know.

Tigerdragon
09/30/2015, 01:03 PM
Nitrate tester would be nice the alk they have is fairly close but the ca tester have found to be off quite a bit as compared to red sea wonder why

outssider
09/30/2015, 04:14 PM
Nitrate tester would be nice the alk they have is fairly close but the ca tester have found to be off quite a bit as compared to red sea wonder why

I think part of the problem is trying to draw 1/10 ml of sample accurately, is that like 1 and 1/2 drops ? 1 drop ? 2 drops ? :lolspin: it's going to make a big difference in the results...

Scubajoe1
09/30/2015, 09:15 PM
Nitrate tester would be nice the alk they have is fairly close but the ca tester have found to be off quite a bit as compared to red sea wonder why


Not quite sure why it's off unless that battery needs changing. I made a 400 ppm solution of Ca in the lab, measured it with the Hanna checker and here was my result.
http://i87.photobucket.com/albums/k130/Scuba_joe/396_zpsqvtqnvvs.jpg

Where are you located? I could always mail you a Ca standard and you can see what you get.

I test with my standard every month or so and it's always dead on.

Scubajoe1
09/30/2015, 09:17 PM
I think part of the problem is trying to draw 1/10 ml of sample accurately, is that like 1 and 1/2 drops ? 1 drop ? 2 drops ? :lolspin: it's going to make a big difference in the results...

I have to agree with that statement. I actually use an adjustable 100 uL pipette to measure the amount. You can maybe find a 100 uL syringe online and that would ensure you get an accurate amount of tank water to test.

Tigerdragon
09/30/2015, 09:22 PM
Not quite sure why it's off unless that battery needs changing. I made a 400 ppm solution of Ca in the lab, measured it with the Hanna checker and here was my result.
http://i87.photobucket.com/albums/k130/Scuba_joe/396_zpsqvtqnvvs.jpg

Where are you located? I could always mail you a Ca standard and you can see what you get.

I test with my standard every month or so and it's always dead on.

I am in chico, california and it is a new battery. Could be the testing procedure maybe i am doing it incorrectly i dont know. I wish they would include a cal fluid

Scubajoe1
09/30/2015, 09:25 PM
How much are you off by? with the syringe they supply I would imagine you would have to be within 10% or less.

Tigerdragon
09/30/2015, 09:41 PM
Ok i think i have fig it out. It has been how i have been running the tests. This eve i did alk and ca with my red sea got alk at 11 and ca at 430. I just ran these with my hanna meters making sure i followed the steps in the right order and correctly alk came in at 11.2 and ca at 432. Had to be me and the way i was doing it

Tigerdragon
09/30/2015, 09:43 PM
I had been off as much as 60 so with what i got tonight it was an error in procedures on my part

zzz111
09/30/2015, 09:50 PM
How much are you off by? with the syringe they supply I would imagine you would have to be within 10% or less.

Hi Joe, although the alk checker never failed me, I've never had luck with the green phos or the red ca checker, the HI 93713 portable worked well for me, and i actually use the 25-pack reagent for the small checker, to avoid buying 100-pack or 300-pack a time.

With the HI736 green phos i got 0 to 60 in 3-5 consecutive tests, my guess is the noise level drawns the signal.

With the ca checker, i got anywhere between 420 to 480 in 3-5 consecutive tests, i quit testing it since that. I do use high grade distilled water, people should beware 1ppm Ca in your "water" will show up as 100ppm extra in your testing result. And I do use a 100u pipette. I've contacted hanna to check if I can add that liquid AFTER I mix distilled water and tank water, they couldn't confirm and refused to test the alternative procedure i suggested, which would greatly improve the accuracy: mix 10ml tank water with distilled to make 1L, and take 10ml of that 1L to test.

basically i believe the ca checker test procedure is fundamentally flawed for 3 reasons:
1. diluting sample under test by 100 times magnifies any interference by 100 times
2. diluting x100 at such tiny volume as 0.1ml in 10ml doesn't really help, doing 10ml in 1L would make at least the proportion much more accurate, if hanna can actually confirm a slightly modified procedure, or if they agree to sell the reagent cheap in gallons then the current procedure is fine too
3. diluent water purity too critical, as Ca in it gets magnified by 100 times, yea i know it's good business selling water at $20 a small bottle but people are simply not buying it, and often times home made RODI is not good enough for this task

zzz111
09/30/2015, 10:01 PM
wondering if you guys tried 3-5 consecutive tests in a row? I always do that with whatever testing product first time i open it, while most of them are ok with acceptable consistency, i never got hanna hi736 low phos and hi758 ca to give me any consistency i can swallow.

Scubajoe1
09/30/2015, 10:19 PM
I have done maybe 3 in a row and get fairly reproducible results. One thing you need to make sure is that the cuvette is wiped of all fingerprints. This is especially critical for the phosphorus or phosphate test. I have also measure before got a strangely high reading and then washed out the vial with soap and winded with RO water.

Also I would just check the RO water alone and make sure that gives you a 0 reading.

One other thing for the phosphate and phosphorus....you need to gently turn upside down and right side up. I have seen some youtube videos where people shake the hell out of the tubes which makes lingering bubbles.

Not as critical for Ca because that changes color big time. I have seen where the Ca test also read lower than I expected and then noticed there was reagent still left in the packet. Agreed these are not the best packets for dispensing. Once I made sure I have expanded the inside corners with my finger so no reagent gets trapped then I was able to get reproducible results.

zzz111
09/30/2015, 11:24 PM
Maybe just my units having extra high noise background. I've been using hanna portable since 2007 and checkers as soon as available on market, with all the precautions like cleaning then never touching the vial other than at the top tip or bottom, aligning the vial the same between zeroing and testing, etc. some just work fine, and the phos and ca just don't work.

The phos checker gave me very repeatable results at PO4 > 0.5ppm, but at lower range it just generates random numbers for me, doesn't matter if you put distilled water or <0.05ppm tank water to the test. While with the Ca checker, I bought my 100u pipette just for it and used high grade pure water as diluent, it just jumps between 420 to 480 when testing tank water time and time again from the same cup. That's why I guess it's the background noise level in the circuitry.

Giovanni
10/01/2015, 11:17 AM
When using the hanna CA unit I use a 0.5ML syringe made for insulin injection and it works well. I just prefer titration reaction type kit over the complicated hanna Calcium procedure.

nuxx
10/01/2015, 11:22 AM
Count me in on a Nitrate checker from them!

All I really care about is ALK, PO4, Calcium and Nitrate.

3 out of 4 covered already :)

Scubajoe1
10/01/2015, 11:38 AM
When using the hanna CA unit I use a 0.5ML syringe made for insulin injection and it works well. I just prefer titration reaction type kit over the complicated hanna Calcium procedure.

Complicated? You add water and 1 ml of reagent A, take a zero reading then add 0.1 ml salt water and a packet and mix and read for the most part.

Giovanni
10/01/2015, 03:30 PM
Complicated? You add water and 1 ml of reagent A, take a zero reading then add 0.1 ml salt water and a packet and mix and read for the most part.


More so than a scoop of A, 8 drops of B and Titrate C.

zzz111
10/01/2015, 07:08 PM
Hi Joe, could you ask them why they can't replace the powder packs with some liquid reagent? Asking because I remember an Italian reefer once posted saying folks in europe use a liquid reagent from some other vendor with hanna testers, worked fine. I personally use HI736 reagent with HI93713 portable, works fine, my guess many of them are just the same. But why can't hanna offer it in liquids? I couldn't find that europeon product here, and forgot the name.

bertoni
10/01/2015, 09:28 PM
Liquid reagents often are less stable than dry reagents. That might have something to do with the choices made. I'm not enough of a chemist to be sure of all the possible issues.

Scubajoe1
10/02/2015, 07:17 PM
I know that is why red sea switched from liquid to solid reagents. They said the liquid reagents were not as stable for their older nitrate pro test kit. I am quite certain J. Bertoni is correct here on his assumption.

bertoni
10/03/2015, 07:47 PM
I used some of their old kits with liquid reagents. I bought one set, it failed badly, and I moved on to another brand.

Scorpius
10/03/2015, 09:36 PM
I think a lot of people who are not chemists, like me, would prefer the display in dKH.

Because it's so hard to multiply by .056? :hmm4: We have a thing called a calculator or a pen and paper if you prefer. :lol: Just a friendly nudge. :)

laga77
10/04/2015, 07:11 AM
Lastly, As we have the alkalinity Checker for saltwater aquariums, I am curious if we should offer a unit that displays in dKH as opposed to calcium carbonate. It seems that in the forums dKH is more common. Since it is only a change in programming it would be relatively easy to do as well.


This was the reps question and I agree with what he states. Most hobbyists use dKH. Therefor, why not display the format most used?

2una
10/04/2015, 04:29 PM
Well if this thread gets forwarded to Hanna to view........

Would be keen to see a No3 also.
dkh YES
On the Po4 ULR that add packet & shake for 2mins & clean the bottle & get it back in with a 3mins shutoff is a stop watch procedure....only way i get it done is to pour the packet out into a piece of bent cardboard to get it all in & within time.
Works but times fine....

Scorpius
10/04/2015, 05:59 PM
Well if this thread gets forwarded to Hanna to view........

Would be keen to see a No3 also.
dkh YES
On the Po4 ULR that add packet & shake for 2mins & clean the bottle & get it back in with a 3mins shutoff is a stop watch procedure....only way i get it done is to pour the packet out into a piece of bent cardboard to get it all in & within time.
Works but times fine....
Use both vials. One which will be used to zero out the Checker. Use the other one to test.

Add your reagent into one of the vials and shake as long as you need to.
Then add the vial without the reagent into the checker to zero out the checker.
Finally add the vial with reagent you already shook up into the checker to test.

It's not rocket science guys, you just have to be diligent when doing these tests.

Scubajoe1
10/07/2015, 06:46 AM
you do not want to use separate vials. If there are any differences in the glass from one vial to the other this will add or subtract from your reading. Just saying.

Scorpius
10/07/2015, 10:44 AM
you do not want to use separate vials. If there are any differences in the glass from one vial to the other this will add or subtract from your reading. Just saying.

I'll go put that extra vial in my curio cabinet to look pretty then. :lmao:

amcvay1979
10/07/2015, 10:51 AM
my biggest issue w/the Hanna checkers are when opening a new reagent bottle for ALK, just for fun I grabbed 2 tank water samples. Compared open bottle reagent to new reagent. Open bottle was giving me consistently high readings. New un-open reagent was giving a very low ALK number that continued to read low every day. So which one do I trust? The one saying my Alk is 8.2 or the one saying my ALK is 6.8?

Giovanni
10/07/2015, 10:54 AM
my biggest issue w/the Hanna checkers are when opening a new reagent bottle for ALK, just for fun I grabbed 2 tank water samples. Compared open bottle reagent to new reagent. Open bottle was giving me consistently high readings. New un-open reagent was giving a very low ALK number that continued to read low every day. So which one do I trust? The one saying my Alk is 8.2 or the one saying my ALK is 6.8?


Use some two part to make a known test solution.

amcvay1979
10/07/2015, 01:53 PM
Use some two part to make a known test solution.

What would the recipe be to make a known solution? I use Seachem Reef Advantage 2 part.

bertoni
10/07/2015, 04:40 PM
I can look up a formula for a 2-part standard, but it will require a precision scale. What do you have available?

Giovanni
10/07/2015, 06:34 PM
Use 5 gallons of RODI to 3 grams of dry soda ash or 4.7 grams of dry sodium Bicarbonate to make a 150 PPM solution. If you use a smaller volume of water errors in measuring will make a larger error in final concentration.

Ontheway
10/07/2015, 10:52 PM
my biggest issue w/the Hanna checkers are when opening a new reagent bottle for ALK, just for fun I grabbed 2 tank water samples. Compared open bottle reagent to new reagent. Open bottle was giving me consistently high readings. New un-open reagent was giving a very low ALK number that continued to read low every day. So which one do I trust? The one saying my Alk is 8.2 or the one saying my ALK is 6.8?

You can buy a Salifert kh test kit and use supplied standard liquid in it to test Hanna Checker (of course, you can use the kits itself, too :) )

Praslin
01/18/2016, 01:39 PM
Found this in Science Direct
Maybe this is the way to go....no more cadmium?

Michigan Technological University
http://journals.plos.org/plosone/article…
Open-Source Photometric System for Enzymatic Nitrate Quantification
B. T. Wittbrodt,
D. A. Squires,
J. Walbeck,
E. Campbell,
W. H. Campbell,
J. M. Pearce
Published: August 5, 2015
DOI: 10.1371/journal.pone.0134989
-------------------
Praslin

bertoni
01/18/2016, 07:15 PM
That link doesn't work due to cut and paste issues, but I don't think cadmium in a nitrate test kit is particularly dangerous. I don't know what reagents that test might use, but enzymes might be rather hard to get.

Praslin
01/19/2016, 12:59 AM
Nitrate reductase , prod of it is rather standard procedure, It might be a step in the right direktion ,or..? :)

Praslin
01/19/2016, 02:42 AM
Nitrate reductase , prod of it is rather standard procedure, It might be a step in the right direktion ,or.... to complicated or expensive ...? :)

Sorry for the wrong link ,Think this is the right link
http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0134989

Thought you guys who are in to it could evaluate this new device or method.
Have a nice day
Peter

sanamyan
01/19/2016, 04:41 AM
Hi Joe, could you ask them why they can't replace the powder packs with some liquid reagent? Asking because I remember an Italian reefer once posted saying folks in europe use a liquid reagent from some other vendor with hanna testers, worked fine.
I use my own home made liquid reagents with hanna phosphate and hanna phosphorus meters, they work fine and I have much more stable results with them than with hanna's dry reagents which are inconsistent. This is a standard ascorbic acid - ammonium molybdate method (described in many sources in internet), four solutions: ascorbic acid, sulfur acid, Potassium antimony tartrate and ammonium molybdate (everuthing except sulfur acid are from ebay). Sounds complicate but actually not, and I'm not a chemist. Extremely cheap.

bertoni
01/19/2016, 09:48 PM
That does look like an interesting approach. As a DIY project, it might be a lot of fun and quite useful for measuring nitrate. I'm not sure how well it'd measure on the low end, though. They tested down to only 2.2 ppm or so.

Ellery
02/25/2016, 11:59 PM
I've been looking into the DIY Nitrate Photometer myself but haven't received a response back from the Prof Pearce if the photometer would read the color accurately for existing Test Kit Reagent , like from Red Sea. the cost of the reagents on the nitrate.com website seems fairly high.

Has any one even tried to build this yet?

bertoni
02/26/2016, 12:33 AM
At the least, you'd have to make your own calibration curve for the device. I doubt that the other reagents would have the same light absorption characteristics.

Ellery
02/26/2016, 05:56 PM
Too bad the Mindstream monitor I signed up to Beta Test isn't out yet. I wished they would include a Saltwater specific configuration so we can have Alk, Ca, Mg, Nitrates, Salinity, PH, PO4, on a realtime access.

The Hanna Nitrate Photometer would have been the cheaper alternative if it worked with saltwater.

atraperegrinus
03/01/2016, 06:00 PM
Honestly for the alk and phos checkers, since they said its just a simple programming change for DKH to show up, i almost wonder why they don't just offer it either way? it can't be that big of a change. And I bet the ones showing DKH would sell better.

even if it is just a calculator or paper and a few seconds, its still 1 step you wouldn't NEED to worry about. Funny how people complain about the extra minute or so for a calcium checker test, but then pass on something that saves you time for no penalty whatsoever.

jason2459
03/01/2016, 09:06 PM
They do have an Alkalinity Checker that displays in dKH now.


http://www.reefcentral.com/forums/showthread.php?t=2559570

SexyRob
03/02/2016, 07:57 AM
please make a nitrate checker hanna

nogascans
03/02/2016, 02:07 PM
Quite correct. I picked one up thru Hanna and it works well. Same basic testing premise as with older unit, so its an easy learning curve.

Sincerely,

David

They do have an Alkalinity Checker that displays in dKH now.


http://www.reefcentral.com/forums/showthread.php?t=2559570

Dan_P
03/02/2016, 04:36 PM
you do not want to use separate vials. If there are any differences in the glass from one vial to the other this will add or subtract from your reading. Just saying.

Actually, if you get away from those expensive Hanna vials and buy a dozen three dram vials with lids (!) for < $20 through Amazon, you can find two vials that look the same to the Checker. In my batch, I found many "identical" pairs.

RobbyG
03/04/2016, 12:43 PM
I had a long chat with a Hanna Rep about the Nitrate testing. My question to them was the typical one of why don't you make a Nitrate Test Kit and he responded that he knew it was a popular request but they had tried but there were issues and they were not happy with the results.

As an EE I asked him what was the technical problem, the typical Nitrate kits use a color change and Hanna kits use a color change so whats the issue. He told me that they only can read within a small spectrum and most kits go from a wide color spectrum. For example API going from Yellow to Red so he said they cannot read such a broad color change using the photometers for just a specific wavelength.

At that point I chuckled and said to him, we are not interested in what happens after 10ppm what we want to know is all in that yellow region. So why not build a ULR Nitrate reader that maxes out at 10ppm. I then forwarded him some of Randy's info on ideal parameters and he got back to me and said this could work, he had no idea we only needed to read such low values and he was going to talk to the top brass and present them with the information I provided.

So fingers crossed guys, they might come out with something fairly soon.

Rob

JOEYRM7
03/04/2016, 02:51 PM
RobbyG

Well put. It amazes me that a company that supplies products to a niche clientele would not have a better understanding of their needs. I hope that this goes somewhere as I prefer the digital results over other test kits as many of us do.

RobbyG
03/04/2016, 04:38 PM
RobbyG

Well put. It amazes me that a company that supplies products to a niche clientele would not have a better understanding of their needs. I hope that this goes somewhere as I prefer the digital results over other test kits as many of us do.

Thanks.
I think they kept looking at other popular kits that read up to 80ppm and above and thought that was what was needed. I explained that any serious Aquarium owner is looking at below 1ppm. I said if we ever need to read past 10ppm we will buy a cheapo API kit or dilute the water and do the math. What we do need is a digital readout for Ultra low Nitrate because these color wheels and charts are just not cutting it.

Rob

Happyschneider
03/04/2016, 05:12 PM
Could we also ask them to have the last reading displayed when the reader is woken from sleep? How often have missed the reading because I was concentrating on another test. Or make them beep when the result is ready. Or put Bluetooth into them and sync to my phone ;)

And why are the vials round?

DamonG
03/04/2016, 08:49 PM
I had a long chat with a Hanna Rep about the Nitrate testing. My question to them was the typical one of why don't you make a Nitrate Test Kit and he responded that he knew it was a popular request but they had tried but there were issues and they were not happy with the results.

As an EE I asked him what was the technical problem, the typical Nitrate kits use a color change and Hanna kits use a color change so whats the issue. He told me that they only can read within a small spectrum and most kits go from a wide color spectrum. For example API going from Yellow to Red so he said they cannot read such a broad color change using the photometers for just a specific wavelength.

At that point I chuckled and said to him, we are not interested in what happens after 10ppm what we want to know is all in that yellow region. So why not build a ULR Nitrate reader that maxes out at 10ppm. I then forwarded him some of Randy's info on ideal parameters and he got back to me and said this could work, he had no idea we only needed to read such low values and he was going to talk to the top brass and present them with the information I provided.

So fingers crossed guys, they might come out with something fairly soon.

Rob
Is there any way we can contact Hanna to support this request? I spoke with them and they explained to me the same about the difficulty of making the kit. I never was advised it is the range.. But I agree, and ulr would be awesome!

And if I, at least can support the request, that would be awesome!

dkeller_nc
03/04/2016, 09:41 PM
Honestly, their explanation doesn't make a lot of sense. The reduction of nitrate to nitrite and detection via the Griess reagent is straightforward and works quite well in a seawater matrix. And it's been the standard method in oceanography for decades. The UVmax for the diazonium salt is around 550 nm, which is easy from an electronics viewpoint.

But then again, this is the same company where some goofball thought it was wise to save a few batteries by setting an auto-off timer of 3 minutes. I understand they've lengthened it to 10 in some of the newer meters, but it's still a very inconvenient "convenience feature".

I can assure you that I'd be very unhappy with a company that made a lab-grade spectrophotometer that went "off" after a few minutes of inactivity to save a few hours of lifetime on a deuterium or tungsten lamp.