hanna ULR phosphorus checker question

[vijaym85]

So I got this new checker just 2 days ago and already I am having an issue with it.
The unit turns off to "save battery life" in a absurdly fast 2min of non use. Therefore from the time I zero the unit with water it becomes a race against the clock to pour in the reagent and dissolve it. The problem is the powder reagent never dissolves within the 2min period. Also shaking in a vigiorous manner can create air bubbles which is also detrimental to the reading I may get. So basically everytime I get the reagent to dissolve, the unit has shut off.
I have even resorted to swirling the mixture and placing it in a plastic bag and submerging it in a hot water bath to help induce greater solubility. This method has also been to no avail.
So the only method that I find that has any level of promise is using 2 cuvettes, one to zero the unit, and the other which contains predissolved reagent in the test sample. Does this seem like it would provide accurate results though? My main concern would be with the glass itself and any inperfections which may vary between both cuvettes, and I imagine it will worsen with age and repeated use.

 

[bertoni]

I wouldn't use two cuvettes if I were interested in the most accuracy, but it might be close enough. You could try measuring the cuvettes, preferably multiple times, to see how much variation you get.

Maybe someone with more experience with the unit can help you reduce the time required to take the test.

 

[reef_doug]

Agree the 2 minutes doesn't really give enough time. I add the powder, close the lid and invert upside down about 30 times. I don't shake it as this would add excessive airbubbles that may not rise when the 2nd reading takes place.

Another trick mentioned is to mark the curvette with a Sharpie pen just below the lid and a mark on the checker. This will help you align the curvette in the same orientation each time you insert it into the checker to minimize any curvette glass errors.

I wouldn't use the two curvette method.

 

[m2434]

It's 3 minutes, but still short.

What I do now is, open reagent, fold a piece of paper in half. Pour the reagent in the crease. Wipe off all fingerprints from the vial. Go through C1 and C2 steps. Pull the vial about half way out, by the cap. Add the reagent from the paper. Put the cap back on. Shack the hanna meter, without removing the vial further.
I shake it for about 1:45 not 2 minutes, then tap it gently for a few seconds to let it settle and get rid of any bubbles. I'm told you only need to shake it long enough for the reagent to react with the phosphorous. If there is less P, then less is fine. Some people do less than this even.

 

[FocusFin]

I appreciate that they want to save me from buying another battery but I'd be willing to spring for a new one sooner if they gave me say 5 minutes instead

 

[vijaym85]

I first purchased their alkalinity checker which has a 10min auto off and it uses liquid reagent. Not sure why they thought to make this one so short considering it uses a powder. I think the checker is a nice idea but flawed by this "supposed feature"
I am going to try to do what has been said and keep the orientation of the cuvette in relation to the meter unchanged and see if it helps achive better results.
But should I go ahead with the test if some reagent has not dissolved and it's about to become 2min?
The only reason I used the 2 cuvettes was that I had alreadly mixed the reagent in and was trying to dissolve it but suddently the unit shut off. So instead of throwing away and wasting the reagent I thought I would re-zero the unit again and use the test sample I would have thrown out. I know this is not ideal, I will try and give your suggestions a try.
I feel like im going to spend way more money buying reagents at this rate and would be happy to rather buy a spare battery instead.
thanks for all your responses.