Hannah Nitrate HR False Low Readings

[Miami Reef]

Does anyone have suggestions for a different nitrate test brand? I want something that is decently accurate and precise. I value precision over ease of use.

 

[Saltyanimals]

I been testing both NO3 and PO4 with Hannas every other day while I’m tuning some things. I also have noticed an occasional dramatic dip on both on the same testing day. At first I though my tuning experiment kicked in double time only to see the test 2 days later back to the expected curve. This could only mean testing error. What I found was interesting was BOTH had testing errors on the same day.

Theory is cross contamination of residual mixing reagent. I try to rinse many time of course. Then always do 2 fills of the vials in tank water before using the 3rd fill for the actual test. Maybe somewhere in my work flow some undissolved residuals stuck around. One should try and keep the glass separated but bit harder if you’re doing very frequent and a lot of testing. Just a theory for now.

 

[ryshark]

I been testing both NO3 and PO4 with Hannas every other day while I’m tuning some things. I also have noticed an occasional dramatic dip on both on the same testing day. At first I though my tuning experiment kicked in double time only to see the test 2 days later back to the expected curve. This could only mean testing error. What I found was interesting was BOTH had testing errors on the same day.

Theory is cross contamination of residual mixing reagent. I try to rinse many time of course. Then always do 2 fills of the vials in tank water before using the 3rd fill for the actual test. Maybe somewhere in my work flow some undissolved residuals stuck around. One should try and keep the glass separated but bit harder if you’re doing very frequent and a lot of testing. Just a theory for now.

I feel like they are both very accurate. I use the same vial for the tank water as the actual test. After I’m done I rinse the vial 4x.
3x with tap water and the last rinse with RODI. Then wipe it down and put it away.

 

[VexedTomb792]

If you have any API nitrate tests around, you can use them in the hanna HR as well, if you wanted to compare results.

Reef builders had an article on it, and they found the API solution was accurate in ranges above 5ppm, and varied from hanna when in the lower ranges.

Am I reading that correctly? You can use API reagents in a hanna tester?

 

[Miami Reef]

Am I reading that correctly? You can use API reagents in a hanna tester?

I believe so. I believe @Dan_P and @taricha did it.

I don’t seem to be having the Hanna nitrate test issue anymore. :)

 

[BryanM]

I’m having an issue with my HR Nitrate checker.

I know my nitrates are around 8ppm because my tester always tests around that, and I’m not using a nitrate reduction method. It also comes close with my ICP readings.

The other day I tested (emptying the whole packet of reagent, as usual) but while shaking, I noticed the color was very light in comparison to how it usually is.

I got a result of under 1ppm. I immediately tested again and the second time came around 8ppm.

I started feeding heavier lately, and yesterday I tested with a similar outcome: unusually light pink with results around 2ppm, I tested again and results came 9.5ppm.

I use my vials for both the nitrate and phosphate ULR test. I rinse thoroughly with RO/DI and then rinse with saltwater prior to testing.

The whole packet of reagent is added. Anyone else have a similar experience?

I've had this happen as well, and when I get results that are unexpected I Just re-test.

Occasionally I open a packet and its cakey, I just toss it, I don't even bother trying to use it to test.

 

[VexedTomb792]

I've had this happen as well, and when I get results that are unexpected I Just re-test.

Occasionally I open a packet and its cakey, I just toss it, I don't even bother trying to use it to test.

Good job the packs of reagents are so cheep then :)

 

[awokenreefboy]

Luckily I haven’t experienced this issue yet. I’ve gone through several re-fills of Hanna reagents, from testing these parameters every other day.

Phosphate ULR
Nitrate HR
Alkalinity

They all seem consistent and accurate. (Aside from the one time I used an old bottle of Alk reagent that had been open for months)

Same here.

Never had a problem with Nitrate, Phosphate, or Alkalinity and I’ve gotten new reagents for all of them. I did have a problem with the Calcium Checker.

I do make sure to wash each vial AND syringe with soapy water then a RODI rinse.

 

[Malcontent]

Same here.

Never had a problem with Nitrate, Phosphate, or Alkalinity and I’ve gotten new reagents for all of them. I did have a problem with the Calcium Checker.

I do make sure to wash each vial AND syringe with soapy water then a RODI rinse.

Why soap?

 

[exnisstech]

Why soap?

Curious as well. I use 12 vials when I test (4 tanks) and they each get 3 rinses at the RO faucet shake and wipe and back in the case. I've been doing nothing more than that for years and its never been an issue .

 

[Dan_P]

Am I reading that correctly? You can use API reagents in a hanna tester?

The reagent ratios will need adjusting and the Hanna recalibrated. Not a big deal but could be daunting if chemistry lab disturbs you.

Keep in mind that the quality of API reagents can vary much more than Hanna reagents. You might need to recalibrate the Hanna Checker every time you change reagent lots. This is why I don’t use API anymore unless it’s an emergency. This doesn’t mean API reagents are bad. The need for high consistency isn’t needed as much as with a photometer-based method.

By the way, any colorimetric method, any manufacture, as long as the test solution is clear can be measured with the appropriate Checker.

 

[Miami Reef]

Soap isn’t necessary IMO.

 

[Dan_P]

I’m having an issue with my HR Nitrate checker.

I know my nitrates are around 8ppm because my tester always tests around that, and I’m not using a nitrate reduction method. It also comes close with my ICP readings.

The other day I tested (emptying the whole packet of reagent, as usual) but while shaking, I noticed the color was very light in comparison to how it usually is.

I got a result of under 1ppm. I immediately tested again and the second time came around 8ppm.

I started feeding heavier lately, and yesterday I tested with a similar outcome: unusually light pink with results around 2ppm, I tested again and results came 9.5ppm.

I use my vials for both the nitrate and phosphate ULR test. I rinse thoroughly with RO/DI and then rinse with saltwater prior to testing.

The whole packet of reagent is added. Anyone else have a similar experience?

There is an occasional bad packet of reagent that is easily spotted. You can detect these by whether or not the reagent is a free flowing powder. If it clumps, cakes like flour, or looks like a damp powder, throw the packet away.

I have no idea how this could happen within the same lot of reagent and in a string of good packets. The reagent has improved though over time. This happened more frequently when the high range first came out.

 

[Miami Reef]

There is an occasional bad packet of reagent that is easily spotted. You can detect these by whether or not the reagent is a free flowing powder. If it clumps, cakes like flour, or looks like a damp powder, throw the packet away.

I have no idea how this could happen within the same lot of reagent and in a string of good packets. The reagent has improved though over time. This happened more frequently when the high range first came out.

Yes. This thread was made in 2022.

I don’t have this issue anymore. :)

 

[Malcontent]

I have no idea how this could happen within the same lot of reagent and in a string of good packets. The reagent has improved though over time. This happened more frequently when the high range first came out.

Could be that they purge the packets individually with nitrogen and are inconsistent about it.

I don't know for sure how the reagents are made but there's probably a wet stage (in the paper describing the nitrate method they use acetone) so perhaps they don't dry the batch thoroughly.

 

[Dan_P]

Yes. This thread was made in 2022.

I don’t have this issue anymore. :)

I am sooooooo red faced! I am usually pretty good about checking the dates.

 

[VexedTomb792]

I am sooooooo red faced! I am usually pretty good about checking the dates.

My fault, i woke it up. Just got my first hanna tester and put it in the search bar. Just so you know the 1st reagent packet in my NEW nitrate HR checker (MF date Jan 25, direct from Hanna) was clumped together in 1 lump. The second was fine so I don’t think they’ve absolutely bottomed out the issue yet.

 

[awokenreefboy]

Why soap?

Curious as well. I use 12 vials when I test (4 tanks) and they each get 3 rinses at the RO faucet shake and wipe and back in the case. I've been doing nothing more than that for years and its never been an issue .

Soap isn’t necessary IMO.

I mean rinsing it in RODI is probably fine, but in every laboratory setting I’ve been in, everything is washed in some type of solution, and even autoclaved. So yeah, that’s why I use soap… I like to think of it like putting your pellet food in the fridge - do you need to? Probably not. Does it hurt? Highly unlikely.

Just think about if you were to pay for an ICP test. Would you want them to just rinse all their equipment in RODI, or would you want them to professionally clean their equipment every time?

Yeah it’s a total pain in the butt, but it probably just adds an extra 30 seconds to the cleaning process. Tedious, but worth it for my peace of mind!

 

[exnisstech]

I mean rinsing it in RODI is probably fine, but in every laboratory setting I’ve been in, everything is washed in some type of solution, and even autoclaved. So yeah, that’s why I use soap… I like to think of it like putting your pellet food in the fridge - do you need to? Probably not. Does it hurt? Highly unlikely.

Just think about if you were to pay for an ICP test. Would you want them to just rinse all their equipment in RODI, or would you want them to professionally clean their equipment every time?

Yeah it’s a total pain in the butt, but it probably just adds an extra 30 seconds to the cleaning process. Tedious, but worth it for my peace of mind!

I'm sure it can't hurt. I'm just lazy and also I've never been in a lab so I'm rolling with ignorance is bliss lol

 

[ryshark]

I’ve washed the cuvettes in RODI and I’ve washed in tap water. Makes no significant difference.