I’ve never (that I know of) had problems with my Hannah checkers. I’ve got the same 3 it sounds like you had. How far off were they?
Hanna checkers reporter the following:
Ca 435
Alk 8.5
Po4 .02
For the salifert
Ca 340
Alk 9.6
Po4 .15.
Not too bad for the Po4. but the rest it’s an issue. Now i know why I was getting stns and rtns. [emoji2959]
By the way, someone told me the other day that I should mark the covet when I get the first reading, and then place it the same exact way when doing the second test. This is I guess due to the imperfections on each covet that may affect the readings. Haven’t tried it yet...
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