Hanna checker

[Hilltopreef90]

I recently tested my aquarium and was shocked when it read 75.6 nitrate, I began to suspect the checker wasn’t working properly when two other tanks measured in the same range, one that hasn’t even had fish and is cycling.
How can I reset or find out if the checker is not clearing properly or if something is dirty ?
It’s a nitrate HR checker does it matter if it’s high or low range ?

 

[homer1475]

Do they have standards for the HR checker yet?

Would be the only way to know if the electronics are working properly.

https://www.saltwateraquarium.com/h...MIgNuEsfWX9QIVNSc4Ch3IFQ1FEAQYAyABEgKhuPD_BwE
Used to own the LR, its a huge PITA to use. The high range is the one you want to use.

 

[Little c big D]

Could there be and smudging on the vial or anything that had gotten inside? I know this probably isn't the case here but it's good to rule out the easy stuff. I would take it and some water to an lfs of they use hanna as well and have them test it next to yours.