C. Eymann
2500 Club Member
Hello,
I have gone through several boxes of HI774-25, Lot # H015 and have been getting wonky high results in about 60-70% of the packets in each box, seems to vary by box though.
Before "user or test error" is going to be the "go-to" response.
I work at a coral aquaculture facility and am responsible for daily testing and adjustments of all the systems water chemistry.
I perform at least 15 phosphate tests everyday, sometimes more, I have never had issues with the HI774 or HI736 checkers or the reagents they use.
I am very thorough in testing procedures, using the same unblemished curvettes, clean syringes, no smudges etc etc,
I do love both these instruments, they are wonderful, However, these last few boxes of HI774-25 reagent refills I have used give me wildly inaccurate results, the sample turns dark blue before its even time to take measurement, I get .76 or even "out of range" compared to salifert PO⁴ kits .10 results, I used a new 736 ULR checker and reagent and the results were in the neighborhood of which is in normal expected ranges. I do understand that phosphate and phosphorus results will differ a little bit, but not much after conversion. But not 18ppb on a HI736 and .77 or even .90 (flashing) =out of range on a 774. same when a salifert test is showing me around .1 on the same sample.
I opened a new sample syringe, new curvette, etc etc to ward out possible contamination, its not the checker either, its the reagent, it starts turning dark blue visually when agitating/mixing the sample on systems that normally the hint of blue should barely be registered by the human eye before initiating the colorimeter test.
Did you guys maybe send out a bad batch? could this be caused by extreme temperature exposure during transit ? why would some packets in the same box/roll give me reasonable results where as the majority are obviously defunct/bad?
Again, I have yet to have any problems with your hanna phosphate/phosphorus checkers in the past year, until now. I have ruled out any variables that could have been corrupting the tests.
Please advise
Thank you
I have gone through several boxes of HI774-25, Lot # H015 and have been getting wonky high results in about 60-70% of the packets in each box, seems to vary by box though.
Before "user or test error" is going to be the "go-to" response.
I work at a coral aquaculture facility and am responsible for daily testing and adjustments of all the systems water chemistry.
I perform at least 15 phosphate tests everyday, sometimes more, I have never had issues with the HI774 or HI736 checkers or the reagents they use.
I am very thorough in testing procedures, using the same unblemished curvettes, clean syringes, no smudges etc etc,
I do love both these instruments, they are wonderful, However, these last few boxes of HI774-25 reagent refills I have used give me wildly inaccurate results, the sample turns dark blue before its even time to take measurement, I get .76 or even "out of range" compared to salifert PO⁴ kits .10 results, I used a new 736 ULR checker and reagent and the results were in the neighborhood of which is in normal expected ranges. I do understand that phosphate and phosphorus results will differ a little bit, but not much after conversion. But not 18ppb on a HI736 and .77 or even .90 (flashing) =out of range on a 774. same when a salifert test is showing me around .1 on the same sample.
I opened a new sample syringe, new curvette, etc etc to ward out possible contamination, its not the checker either, its the reagent, it starts turning dark blue visually when agitating/mixing the sample on systems that normally the hint of blue should barely be registered by the human eye before initiating the colorimeter test.
Did you guys maybe send out a bad batch? could this be caused by extreme temperature exposure during transit ? why would some packets in the same box/roll give me reasonable results where as the majority are obviously defunct/bad?
Again, I have yet to have any problems with your hanna phosphate/phosphorus checkers in the past year, until now. I have ruled out any variables that could have been corrupting the tests.
Please advise
Thank you
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