Check your Hanna Alk Reagent...

[d2mini]

Looks like their is a bad batch out there. My current bottle is part of it.
https://hannainst.wufoo.com/forms/w1hzjs2j1b4ejyu/

Check yours and fill out the replacement form if needed.

edit: didn't see the other thread in the equipment forum. sorry for the DP.

 

[shaggss]

Thanks Dennis!