Hanna Phosphorus checker

[fishbox]

That's part of the debate about proper procedures. Something I thought was weird too, if they suggest you mix for at least two minutes but the unit shuts off 2 minutes after C1. But they also suggest you use the same vial.

Soooooo...

Well someone mentioned that Hanna said to shake for at least 1min 45sec. So that leaves us a 15 sec window.

 

[Krzydmnd]

I also forget often that I set the timer, and it shuts off pretty quickly after results too so I have to run it again lol.

I get saving batteries but it's an lcd screen, it'll run for ever lol.

 

[MnFish1]

My question is not answered in this. My question is why can only the 1st result be read accurately? If done at the recommended 5 minutes I don't see how a second reading within 2 seconds would not be valid. That's what I'm trying to understand. And I believe you stated a few post back that you didn't have the answer for that. My Curious mind just wants to know why with the same reader reading the same solution Within 2 seconds gives us altered results?

It is not valid because the company that designed the product says it may not be reliable. The reader itself isn't designed to do multiple readings. There is no benefit to doing so. What the company stated is if a person wants to recheck their results, the only valid way is through another complete sample. My guess is that these problems occur at higher values of phosphorous.

As fare as the second part - So if you get altered results after 2 seconds - it depends on how different those readings are - if they are within the stated variability of the test - they are really 'the same' result. Every measurement has a margin of error.

 

[MnFish1]

That's part of the debate about proper procedures. Something I thought was weird too, if they suggest you mix for at least two minutes but the unit shuts off 2 minutes after C1. But they also suggest you use the same vial.

Soooooo...

Firstly - they dont suggest you mix for 'at least' 2 minutes - they recommend 2 minutes. They also state that you can stop at 1:45 if you are having problems meeting the time frame - but not to start the 3 minute timer until 2 minutes after the reagent was added.

Secondly, at least on my machine - the checker shuts off 3 minutes after C1 if there is no input.

 

[MnFish1]

Well I do appreciate his input as it has been beneficial to the thread. I just don't agree with him saying that we need to contact Hannah and not ask questions here as no one here will know the answer. It is our job as smart consumers to know the ins and outs of how our products work. It is our job to question why they do certain things and don't have the capabilities to do other things. If it weren't for us as consumers doing that we would never have improvements on products. On top of that it is a very huge claim to state no one else knows the answer besides Hannah. I mean hell if this thread weren't started no one would have made the initial phone call to find out some of the information that he already found out. But someone had to ask the question in order for that information to be put on the form and be shared with others. So again I can appreciate the information that he shared but I'm looking for just a little bit more information.

Thanks - my point was this. Hanna's technical support team said repeat measurements are not to be considered valid. You shouldn't take 3 measurements and average them. So - if the company says that - why would anyone do it?

And lets say someone on this thread said 'its fine to do it' - why would you trust it over what the company said?

My guess is that the reason they use those guidelines is that the test is valid throughout all of the range they provide for phosphorous testing with this meter (0-200). If everyone does it the same way - per the instructions - it means that comparing a test done 1 day to one done a month later is more likely to be valid than if you did the test differently.

 

[fishbox]

As fare as the second part - So if you get altered results after 2 seconds - it depends on how different those readings are - if they are within the stated variability of the test - they are really 'the same' result. Every measurement has a margin of error.

I'm waiting on a new supply of Regent to come in. When it does I'll do some testing to get an idea of the variance. Why do I care? Because regardless of what Hannah tells us if that variance is within acceptable range then it's a very useful tool to get a second reading without going through all the work all over again.

@Forsaken77 do you happen to remember how much of a variance you had?

Secondly, at least on my machine - the checker shuts off 3 minutes after C1 if there is no input.

Man I feel cheated that mine is only 2min [emoji27]

 

[MnFish1]

I'm waiting on a new supply of Regent to come in. When it does I'll do some testing to get an idea of the variance. Why do I care? Because regardless of what Hannah tells us if that variance is within acceptable range then it's a very useful tool to get a second reading without going through all the work all over again.

@Forsaken77 do you happen to remember how much of a variance you had?





Man I feel cheated that mine is only 2min [emoji27]

Sorry - on the first part my question wasnt clear - what are you wanting to use the 'second reading' for? If the 2 results are far apart - it could be because the test isn't designed to be used that way - or it could be one was an error - either way - you have to so a second full test. If they are the within the same variability, then you still haven't gained anything. Im just saying I dont think you can use a second measurement to 'validate' or 'confirm' the initial measurement.

On the second part - Im going to check the time today - and will post back.

 

[Forsaken77]

Then make your point more clearly. Of course you can either use the timer or wait 3 minutes on your own - thats been posted at least once - here - I thought you had some new information. (i.e. you had a different opinion that whats in the instructions).

I'm waiting on a new supply of Regent to come in. When it does I'll do some testing to get an idea of the variance. Why do I care? Because regardless of what Hannah tells us if that variance is within acceptable range then it's a very useful tool to get a second reading without going through all the work all over again.

@Forsaken77 do you happen to remember how much of a variance you had?





Man I feel cheated that mine is only 2min [emoji27]

I'd have to test it again. Haven't been using it lately because I'm prepping a new tank setup. So starting fresh, with the exception of livestock, and haven't been testing the tank that's currently running for a bit.

Anyone that has one can do it. You just tap the button after you get your 3 min reading.

 

[Krzydmnd]

here is some info directly from the horses mouth (Hannas chat feature) answering specific questions regarding one of the discussion points...

I hope it helps a little!

 

[LJC6780]

I’ve done this before. Do you simply click the button for step 2 or do you hold it in until it starts the 3 minute countdown?

I found that when I do the countdown the numbers are pretty steady but if I just click it the numbers are all over the place.

 

[LJC6780]

How are others using the Hanna ULR conducting their test?

My procedure:
1. Wipe cuvette clear inside and out with micro fiber cloth.
2. Tap reagent packet until reagent is gathered in one corner of packet, cut the packet open on right angle sides, fold half of the packet into a triangle pour spout and set aside.
3. Fill cuvette with 10ml tank water.
4. Zero the checker with the same cuvette.
5. Take cuvette out, unscrew the lid and pour/tap reagent into sample water.
6. Recap and shake for 2 minutes (timed on smartphone).
7. Place cuvette back in checker in exactly the same orientation as before.
8. Press and hold down the button until 3 minute countdown counter appears.
9. Sip a cold one until final number appears.

From the way I do it, the reagent is in solution for 5 minutes (give or take a few seconds) until final reading. Should I be waiting longer to take a reading?

this is exactly how I do mine aside from wiping the inside and I wipe the outside again after shaking to remove fingerprints. I also tilt the vial back and forth rather than shaking. Less bubbles that way IME.

 

[LJC6780]

I dont know how you all are able to use the SAME cuvette for this test. When i perform my test i use both cuvettes one with tank water and other with reagent cause in my experience using one cuvette and mixing it for two minutes as the instructions states will cause the device to time out and shut off leaving you with a cuvette full of reagent and a not zeroed out device forcing you to start over and waste a test. IMO that's why hanna includes two cuvettes so you can zero with one and sample with the other.

Get everything ready before you start. Then as soon as it zeros out start a 3 minute timer ... mix for 2 of those minutes and get it in and hold the button for step 2 before the 3 minutes. It times out after 3. Using timers is very handy here as just counting or feeling it just doesn’t work.

 

[XNavyDiver]

this is exactly how I do mine aside from wiping the inside and I wipe the outside again after shaking to remove fingerprints. I also tilt the vial back and forth rather than shaking. Less bubbles that way IME.

The fingerprint thing; I've got a huge box of those latex gloves that I use. That seems to really help.

 

[Robert Staie]

The fingerprint thing; I've got a huge box of those latex gloves that I use. That seems to really help.

Why does Hanna send their quality standards in 2 cuvettes then.

 

[sghera64]

So if you do the 3 minute built-in timer and it displays the reading, you can then immediately press the button again for another instant reading. The instant reading, like 5 seconds after your 3 minute reading, is always usually different.

I just tried to replicate this with my ULR which is about 3-4 years old. After the 3 minute timer (5 minutes after adding reagent and start to mix), I get a reading. My reading was 4 ppb. I hit the button to get a second reading and the unit simple turns off. I repeated this several times and it seems like when I hit the button after I get a reading, that results in turning the unit off. Apparently, you have a "different" version and maybe newer.

Not to upset anyone, but perhaps Hanna included an unadvertised "feature" for those looking for an easter egg hidden in the product and fore those who refuse to simply follow the instructions

[Sorry, MnFish1, I couldn't resist. I know you prefer the pragmatic approach of simply following proven instructions and not deviating. I completely respect that. But, I also appreciate the "playful" and curious folks out there exploring outside the boundaries to see what can be learned. Unfortunately, this often has those curious folks coming back and asking questions that us pragmatists can easily answer with the manuals alone. From you phone calls to Hanna, it seems like they are unwilling to share any more that that either. And I can understand why they don't]

 

[sghera64]

Like MnFish1, my 3 yr old ULR checker will remain on after C2 appears for 3 minutes and 10 seconds. The model before mine did have problems with turning off after about 2 to 2.25 minutes (bummer).

I would be surprised if models recently purchased do not remain on for at least 2.5 minutes.

 

[Forsaken77]

I just tried to replicate this with my ULR which is about 3-4 years old. After the 3 minute timer (5 minutes after adding reagent and start to mix), I get a reading. My reading was 4 ppb. I hit the button to get a second reading and the unit simple turns off. I repeated this several times and it seems like when I hit the button after I get a reading, that results in turning the unit off. Apparently, you have a "different" version and maybe newer.

Not to upset anyone, but perhaps Hanna included an unadvertised "feature" for those looking for an easter egg hidden in the product and fore those who refuse to simply follow the instructions

[Sorry, MnFish1, I couldn't resist. I know you prefer the pragmatic approach of simply following proven instructions and not deviating. I completely respect that. But, I also appreciate the "playful" and curious folks out there exploring outside the boundaries to see what can be learned. Unfortunately, this often has those curious folks coming back and asking questions that us pragmatists can easily answer with the manuals alone. From you phone calls to Hanna, it seems like they are unwilling to share any more that that either. And I can understand why they don't]

Yeah, mine is almost a year old. So it's a newer one. Does yours say in the instructions that you can manually wait the 3 minutes and press the button to instant read after the time elapses? If it doesn't have that feature it won't work.

 

[Fudsey]

I just tried to replicate this with my ULR which is about 3-4 years old. After the 3 minute timer (5 minutes after adding reagent and start to mix), I get a reading. My reading was 4 ppb. I hit the button to get a second reading and the unit simple turns off. I repeated this several times and it seems like when I hit the button after I get a reading, that results in turning the unit off. Apparently, you have a "different" version and maybe newer.

Not to upset anyone, but perhaps Hanna included an unadvertised "feature" for those looking for an easter egg hidden in the product and fore those who refuse to simply follow the instructions

[Sorry, MnFish1, I couldn't resist. I know you prefer the pragmatic approach of simply following proven instructions and not deviating. I completely respect that. But, I also appreciate the "playful" and curious folks out there exploring outside the boundaries to see what can be learned. Unfortunately, this often has those curious folks coming back and asking questions that us pragmatists can easily answer with the manuals alone. From you phone calls to Hanna, it seems like they are unwilling to share any more that that either. And I can understand why they don't]

This is exactly what happens on my tester and it is a new unit albeit bought from a member on here, it was unused. Or at least it looked it and everything was as if it was new. I am unable to press the button for another reading after the 3 minute timer reading, the unit shuts off if I try.

 

[sghera64]

Yeah, mine is almost a year old. So it's a newer one. Does yours say in the instructions that you can manually wait the 3 minutes and press the button to instant read after the time elapses? If it doesn't have that feature it won't work.

My instructions do not say that. However, I have (been a little naughty) and zeroed the unit with a second vial filled only with sample water (C2 appears on screen) and then quickly inserted the reacted sample, after mixing gently for 2 minutes, and pressed the button 1 time quickly(< 1 second) to get a reading at the 2:15 mark. Mine will give me a reading. I know from MnFish1's dialog with Hanna that this reading is likely under reporting the Phosphorous value as the reaction takes 5 minutes to fully develop - - and then it slowly begins to "degrade".

Before this thread was started (like 2 yrs ago), I experimented with a phosphorous standard solution to figure out how this assay worked (just the curious scientist in me). What I observed is that successive readings (I have to turn unit on, see C1, zero it with a blank, see C2 and then take a quick reading - - about a 30 second procedure) increase until about 5-6 minutes, then then decrease a little after that until the 7-8 minute mark. At that point the readings hold fairly steady for 12 more minutes (the 20 minute mark). I did not explore beyond that. I could not determine when in the time range I got a result on the meter that matched my standard, because I could not determine the purity of my solid tri sodium phosphate standard (TSP). So, I have nothing else to resort to but that Hanna says 5 minutes is the optimal time to take a reading. But, what I did learn is that after 7 minutes, the "color" of the reacted sample stays constant. Successive readings went something like this after 7 minutes: 33, 34, 32, 38, 33, 33, 32, 33, 28, 33, 32, 33.

I don't think the reacted sample is increasing and decreasing in color - - that's crazy talk. I think the up and down is due to a random particle in the sample or simply instrument variation. Still, that amount of variation is really small relative to the error (different that variation) that Hanna says the design of the instrument possesses.

One more thing I noticed. Micro bubbles: they are not caused by mixing alone. I prepared one sample by simply emptying a reagent packet in it and letting the powder settle to the bottom - - no mixing, rolling, swirling or shaking. I noticed bubbles forming on the crystals and then from the walls near the bottom. My theory is that as the Ascorbic acid dissolves in sample water (especially water with high alkalinity), bicarbonate and carbonate are converted to carbonic acid to the point of dissolution (CO2 bubbles come out). My technique: to mitigate bubbles, I place the reacted sample into the checker after 2.0 minutes of swirling and press the button (C2 visible on screen) for 3 seconds to activate the 3 minute count-down timer. After 30, 60, 90 seconds, I open the lid and "spin" the vial in the checker - - fast. This causes bubbles stuck to the glass to release and float up. On the third spin (90 seconds), I orient the vial to that the 10 mL label lines up with a mark I made on the white part of the checker. This ensures I orient my sample vial exactly the same each time I use it.

 

[sghera64]

@Randy Holmes-Farley , I believe you have the Hach Pi test kit. If true, does it say anywhere in the kit what method it is based on?

The Hanna ULR checker is an adaptation of the Standard Methods for the Examination of water and Wastewater, 20th edition, Ascorbic Acid method.