Alkalinity dkh tester testing low.

[Brandonsegula]

I've tested with salifert and Red Sea I get 9.5. My lfs is reading the same. I test with my Hanna checker I get 7.8 why is it reading low?

 

[Hanna Instruments]

I've tested with salifert and Red Sea I get 9.5. My lfs is reading the same. I test with my Hanna checker I get 7.8 why is it reading low?

Its hard to say, how old is the Checker? How many tests are left in the bottle? How many tests did you preform with the Checker? What is the reagent lot number/expiration date? Is your syringe that you use clean or dirty? Make sure you follow our 8 Checker best practices blog when using your Checker.