So for over a year iv been using hanna alk test kit and iv notice im dosing double the amount of alk then cal so my mag is 1500, cal 440 and alk was at 8.4 - 8.9 Dkh so i noticed my green hammer was expelling small polyps so i decided to check alk with the salifert test kit i have and it comes up between 12 - 12.8 dkh i tested it 4 times and got the same readings off .1 or .2 different each time all test kits are up to date so im thinking that the hanna isn't what its cracked up to be going to lower alk slowly till i reach 9.0 Dkh