[Timfish]

I'm not surprised. I got a Hanna checker and tested it against a friends. Using my new and thier 6 month old reagent and the same sample of water pulled from the top middle of the tank we got 4 different results that varied by .9 dKH (~.5 dKH with the same reagent). I think APIs Alk test is far easier and may be more accurate if the sample is doubled then divided by 2 (or trippled then divided by 3)