I recently had gotten a refill for my ammonia Hanna checker, started having an error showing up. I changed the battery twice and redone the test about 3 times. Reached out to the store I bought it from to see if they had any idea what was going on or a solution. Which they ended up telling me to call Hanna checker and talk with them. I found out that they had recently changed the formula and now roughly about 10% of the checkers can’t read them, so they are sending a new reagent out to replace the ones that are not reading. If you are having that kind of issue they are helping to resolve the troubles you are having. I’m passing on this knowledge to help another out that may not know of it or knows someone that needs the information.
