Hana ULR Phosphate checker

[Randy Holmes-Farley Verified Community Expert]

Phosphorous LR reagent HI 713-25 lot H102 EXP 08-2019 was 0.03. Phosphorus Ultra OR reagent HI736-0 lot H071 EXP 05-2020 was 27 or 0.083. That is a difference of 0.053.

Which is within the Hanna claimed error of the 713 of +/- 0.04 ppm phosphate and the 736 of +/- 0.015 ppm phosphate. [emoji4]

 

[IslandLifeReef]

So this morning I took a 60ml syringe and drew out 30ml from my DT. I filled 3 test tubes. One for ALK one for Phosphate and one for Phosphorus. Phosphate and Phoshorus were ran the same way. Sample place in machine, button pushed, sample removed and reagent added, tube inverted 100 times, places back in machine, button long pushed, results displayed in 3 minutes. Phosphorous LR reagent HI 713-25 lot H102 EXP 08-2019 was 0.03. Phosphorus Ultra OR reagent HI736-0 lot H071 EXP 05-2020 was 27 or 0.083. That is a difference of 0.053.

Why are you inverting the samples 100 times? The directions say to gently mix for 2 minutes on the ULR checker. I don't know what it says for the LR checker.

 

[Brew12]

One thing I have noticed on my ULR checker is that the placement of the cuvette is critical for repeatability. I only use one cuvette and always point the 10ml sign directly out the front. Once I started doing this I was able to get more consistent results.

 

[MnFish1]

What? That didn’t happen and obviously wouldn’t work.

Your post that I quoted wasnt clear. I quoted it below. It read as if you zeroed with tank water... Fwiw - what solution did you use to zero the test where you tested the reference solution with the hanna checker....

You wrote:

"The meter was zeroed with tank water (always in the checker, then press to start and press when it says '1'. Take out, add reagent, two minutes of inversion, put it back in and hold the button down for the 3-minute countdown. The reference solution (0.08) showed last night a reading of 0.15 (from memory) on the Hanna and zero on the Red Sea kit."

 

[griff500]

One thing I have noticed on my ULR checker is that the placement of the cuvette is critical for repeatability. I only use one cuvette and always point the 10ml sign directly out the front. Once I started doing this I was able to get more consistent results.

I do exactly the same. My issue is not with consistency but with accuracy.

 

[griff500]

Your post that I quoted wasnt clear. I quoted it below. It read as if you zeroed with tank water... Fwiw - what solution did you use to zero the test where you tested the reference solution with the hanna checker....

You wrote:

"The meter was zeroed with tank water (always in the checker, then press to start and press when it says '1'. Take out, add reagent, two minutes of inversion, put it back in and hold the button down for the 3-minute countdown. The reference solution (0.08) showed last night a reading of 0.15 (from memory) on the Hanna and zero on the Red Sea kit."

Just a couple of posts later I confirmed that to test the reference solution I used the reference solution and to test tank water I used tank water.

I understand why you ask, although it would be a bit daft to use two different solutions in one test, but it was covered shortly after in this thread.

 

[MnFish1]

Just a couple of posts later I confirmed that to test the reference solution I used the reference solution and to test tank water I used tank water.

I understand why you ask, although it would be a bit daft to use two different solutions in one test, but it was covered shortly after in this thread.

I understand - for some reason - when I sign on to R2r and click on an alert for this thread for example- im noticing that there are multiple posts before it that I haven't read (even though I clicked on the first alert on my screen). By the way - just trying to help. I have been on the phone with Hanna multiple times about issues of how to do this test and get reproducible results. There are many threads here where various people say 'how they do it differently than the instructions' which is why I was asking you the questions - it was not to criticize you.

 

[griff500]

I understand - for some reason - when I sign on to R2r and click on an alert for this thread for example- im noticing that there are multiple posts before it that I haven't read (even though I clicked on the first alert on my screen). By the way - just trying to help. I have been on the phone with Hanna multiple times about issues of how to do this test and get reproducible results. There are many threads here where various people say 'how they do it differently than the instructions' which is why I was asking you the questions - it was not to criticize you.

No problem and I understand you were trying to help.

 

[rcpalmer1]

Why are you inverting the samples 100 times? The directions say to gently mix for 2 minutes on the ULR checker. I don't know what it says for the LR checker.

In a lab samples are mixed the same way every time to get consistent results. They have machines that rock tubes back and forth the same every time. When i invert the tube the air bubble goes from the top to the bottom. This gently mixes the sample. It takes me approximately two minutes to do it 100 times. Without lab equipment this is the closest I can get to having the sample mixed exactly the same everytime. I feel this is more consistent than a random shake for two minutes.

The procedure for testing is the same for both testers.

 

[rcpalmer1]

Which is within the Hanna claimed error of the 713 of +/- 0.04 ppm phosphate and the 713 of +/- 0.015 ppm phosphate. :)

I agree it is within the stated margin of error. Someone had asked had the two models been compared and since I had both I thought I could share some real world data.

I am not sure everyone understands that the hanna phosphate meter can measure the same sample at 0.1ppm and 0.2ppm and both reading be within the +/- 0.05ppm margin of error stated. I didn't. That is why I bought the phosphorus meter. It stated a +/- 5ppb or +/- 0.031ppm. In effect that would make sample range of 0.1ppm to 0.162ppm or a 0.038ppm more accurate reading.

This was the first time I tested the same sample with both testers. So for both testers to be within their margin of error neither could be correct. But if the two readings are within 0.081ppm of an unknown sample both would have to be considered correct. In this case the phosphorus would have to be reading low and the phosphate would have to be reading high. It would had been nice if the readings had been closer to the same.

 

[gdemos]

One thing I have noticed on my ULR checker is that the placement of the cuvette is critical for repeatability. I only use one cuvette and always point the 10ml sign directly out the front. Once I started doing this I was able to get more consistent results.

Wow, never heard this...

 

[IslandLifeReef]

In a lab samples are mixed the same way every time to get consistent results. They have machines that rock tubes back and forth the same every time. When i invert the tube the air bubble goes from the top to the bottom. This gently mixes the sample. It takes me approximately two minutes to do it 100 times. Without lab equipment this is the closest I can get to having the sample mixed exactly the same everytime. I feel this is more consistent than a random shake for two minutes.

The procedure for testing is the same for both testers.

I was under the impression that the amount of time that the color had to form was important to the accuracy of the test. I tried inverting the cuvette, letting the bubble go from top to bottom, and back again. In two minutes, I was able to invert the cuvette 80 times.

Wouldn't the test be just as consistent if you inverted the cuvette the same way for 2 minutes for both tests? It would be interesting to see if adhering to the time exactly had any effect on the results.

 

[rcpalmer1]

I was under the impression that the amount of time that the color had to form was important to the accuracy of the test. I tried inverting the cuvette, letting the bubble go from top to bottom, and back again. In two minutes, I was able to invert the cuvette 80 times.

Wouldn't the test be just as consistent if you inverted the cuvette the same way for 2 minutes for both tests? It would be interesting to see if adhering to the time exactly had any effect on the results.

Maybe because I have done it this way so many times I do 100 in 2 minutes. That is why I do 100. So the time is the same and it is 2 minutes. If you do it slower, do as many time as it takes you in 2 minutes.

I have on a couple of occasions I not held the button long enough and it took the reading without waiting the extra 3 minutes. I pulled another water sample in a different tube, recalibrated. Then ran the sample with reagent again. The results were still within the margin of error. So at 2 minutes and 5 minutes there is not much difference. I still always follow as the directions as close as possible to get the most accurate test posible.

 

[Randy Holmes-Farley Verified Community Expert]

Timing is important for a phosphate test. High quality tests often specify times (e.g., wait at least X and not more than Y minutes).

So is cuvette positioning if the cuvette is not perfectly symmetric, even including defects and scratches.

 

[IslandLifeReef]

Maybe because I have done it this way so many times I do 100 in 2 minutes. That is why I do 100. So the time is the same and it is 2 minutes. If you do it slower, do as many time as it takes you in 2 minutes.

I have on a couple of occasions I not held the button long enough and it took the reading without waiting the extra 3 minutes. I pulled another water sample in a different tube, recalibrated. Then ran the sample with reagent again. The results were still within the margin of error. So at 2 minutes and 5 minutes there is not much difference. I still always follow as the directions as close as possible to get the most accurate test posible.

Yes, I always follow the time exactly, using a timer each test. In your posts, you said that it was approximately two minutes. You also stated that the tests were within the margin of error, but on either extremity. I was wondering if you adhered to the time exactly, if the results for both the LR and ULR would be closer to each other. If you are using two minutes, then the question is moot.

 

[Bmezz]

Regarding the Hana Phosperous ULR.. anyone have product failure? I have mine for just one year and apparently the button is making functioning and won’t change from “C1”. One year life? Horrible quality I would say?? Comments?

 

[Makers Marc]

My Hanna HI-736 is now showing low or hi light errors eqch time I try and use it. Can someone suggest what to do? Ive used it fine for 12 months.

 

[MnFish1]

My Hanna HI-736 is now showing low or hi light errors eqch time I try and use it. Can someone suggest what to do? Ive used it fine for 12 months.

Did you check the instructions? at least for some it says check the Cuvette for cleanliness?

 

[Makers Marc]

Did you check the instructions? at least for some it says check the Cuvette for cleanliness?

I did. It just states LLO is for low light and HLi is for high light.

Ive wiped the cuvette a ton, since I figured thats the issue. It does it also when theres no cuvette in their after pressing the button after "C1" flashes.

 

[MnFish1]

I did. It just states LLO is for low light and HLi is for high light.

Ive wiped the cuvette a ton, since I figured thats the issue. It does it also when theres no cuvette in their after pressing the button after "C1" flashes.

There is more to it than that - ie it could be a defective cuvette or something confounding the test - I would suggest you call Hanna tech support - they will likely be able to quickly troubleshoot it (they have for me) = let everyone know how it works out. Maybe a defective unit?