I've been tempted to get a few of these, but I can't see myself do getting an alkalinity one, it's just too damn easy to measure with regents and a vial. Put 5mL water in vial, add drops until color changes, count drops you added, that's your dkH. My biggest concern with tank testing isn't how precise it is, but mostly to give me a feel for if something is way out of whack.