Hanna Checker How to Verify

[gabriellar]

Hi I recently got a hanna phosphate LR and hanna phosphate ULR to double check reading on each other. Those give me very different readings: LR says 0.2 and ULR says 0.4. Feel like at least one gotta be bad because the error is at max 0.04 up and down. But I'm trying to avoid paying another 38 dollars on buying the calibration set for both checkers. Any other way to verify the accuracy? I read people don't really trust ICP test, and API test the accuracy level is low. And I don't believe it's human error while doing the test or at least the chance is low -- I made sure all the visible test powders are in the cuvette and nothing spilled, also whipped the glass bottle before each step. But if you see me missing anything that can lead to inaccurate result, please point out. Thanks!

 

[13rodo]

Hi I recently got a hanna phosphate LR and hanna phosphate ULR to double check reading on each other. Those give me very different readings: LR says 0.2 and ULR says 0.4. Feel like at least one gotta be bad because the error is at max 0.04 up and down. But I'm trying to avoid paying another 38 dollars on buying the calibration set for both checkers. Any other way to verify the accuracy? I read people don't really trust ICP test, and API test the accuracy level is low. And I don't believe it's human error while doing the test or at least the chance is low -- I made sure all the visible test powders are in the cuvette and nothing spilled, also whipped the glass bottle before each step. But if you see me missing anything that can lead to inaccurate result, please point out. Thanks!

By chance did you make sure that when you went to take a reading you either a) held down the button to start the countdown b) waiting that time? For the ULR at least I know you are supposed to agitate it for a couple minutes and then wait (I believe 3 minutes) for the reading. If you hold the button down it'll countdown that wait time for you.

 

[gabriellar]

I do (a) the count down for both ULR and LR

 

[gabriellar]

By chance did you make sure that when you went to take a reading you either a) held down the button to start the countdown b) waiting that time? For the ULR at least I know you are supposed to agitate it for a couple minutes and then wait (I believe 3 minutes) for the reading. If you hold the button down it'll countdown that wait time for you.

you mentioned agitate it for a couple minutes, does that mean I should strictly shake two minutes (as the instruction say) before putting in for 3 minuntes count down? I usually do about 150 shakes up and down before I put the cuvette in, but did not count how long did I shake

 

[exnisstech]

2 minutes shaking. In addition to the shaking to mix I think the 2 minutes is part of the count down time needed to get accurate results. I use a timer to count down my 2 minutes so each test is the same. I also use a little magnetic stirrer instead if shaking because I think it's more consistent. I try to do each test exactly the same each time for consistency. Same vial from start to finish, timer and stirrer. Some people use use one vial for c1 and another for c2 which is incorrect and can cause results to vary.

PS my advice is for the ULR since its the only one I've used. I try to avoid multiple testing of the same item being tested to avoid tail chasing. Its more about trying to keep things consistent than obtaining an exact number.

 

[13rodo]

you mentioned agitate it for a couple minutes, does that mean I should strictly shake two minutes (as the instruction say) before putting in for 3 minuntes count down? I usually do about 150 shakes up and down before I put the cuvette in, but did not count how long did I shake

2 minutes is what I do (I gently turn it over, not shake), but admittedly the directions aren't entirely clear. May be worth reaching out to Hanna honestly. Regardless the reported accuracy of the LR & ULR should be relatively in family (like +-0.04). So either user error or something is wrong with one or the other

 

[Reefer Matt]

That’s normal. The Phosphate LR tester is good to .04 ppm +/-, the ULR is good to .02 ppm +/-. So you could have zero.

 

[gabriellar]

That’s normal. The Phosphate LR tester is good to .04 ppm +/-, the ULR is good to .02 ppm +/-. So you could have zero.

Mine is at a different decimal place. It’s 0.4 and 0.2

 

[Mr. Mojo Rising]

I always watch youtube videos for new hanna testers, or even when I haven't used it in while I'll watch a video to refresh myself.

 

[slingfox]

you mentioned agitate it for a couple minutes, does that mean I should strictly shake two minutes (as the instruction say) before putting in for 3 minuntes count down? I usually do about 150 shakes up and down before I put the cuvette in, but did not count how long did I shake

Get one of these and stir for exactly 2 mins:

https://www.bulkreefsupply.com/smar...x4mAJwQa7CQjes8CqTUDdtIu9mx02JZOpPOyZxQZso7CD

 

[gabriellar]

Get one of these and stir for exactly 2 mins:

https://www.bulkreefsupply.com/smar...x4mAJwQa7CQjes8CqTUDdtIu9mx02JZOpPOyZxQZso7CD

Wow I didn't know such thing exist, I'll give it a try

 

[slingfox]

Wow I didn't know such thing exist, I'll give it a try

To use it with the Hanna vials, you need a 3D printed adaptor like this:

https://shop.app/p/7392779665444?va...mpaign=share_product&link_alias=m2XCZlWdVoznn