,Read the instructions... Your ca can't be that hugh
Spoke with BRS, they told me this is a known problem with the CA marine checker, you either luck out and they are accurate or its like mine, I clean the vile before adding it to the checker each time, and clean it after each test ,BRS gave me a refund, I'll toy around with it some more and get my readings from red Sea kit, at least it's giving the same number each time, I have not dosed CA yet until my readings check out. I'll call hannaTake water to your lfs. Have them test your ca. Just to make sure your tester is faulty. Then call Hanna and see what they recommend . Maybe the inner tube is dirty. Or the vials are dirty. Or the testers just bad.