Last week I did my weekly checks and found alk at 5.99 with my Hanna kit. i slug fed sodium bicarb to bring it up and increased my dosing pump quantity a few days later alk barely moved. Slug fed again and checked two days later and alk got worse yet my coral, clams and fish seemed fine. I decided to check with an Aquaforest test kit and got 8.4. So what can be wrong with a Hanna kit. tubes are clean doing the test the same way I have for two years. Should I change the battery even though it seems fine or try another reagent bottle?